4X4 PROBLEM S10 BLAZER

HI THERE.I READ WHAT YOU SAID ABUT THE WIRES ON THE BLAZER,BUT MINE WE NOT CORRODED.I TOOK IT OFF AND CLEANED IT UP ANYWAY,AND IT CAME BACK ON.BUT AS SOON AS I TURNED THE KEY OFF SHE WAS GONE AGAIN.I DONT HAVE ANY LIGHTS LIGHTING UP ON THE 4X4 SWITCHES.SERVICE 4X4 LIGHT IS ON IN THE DASH.DONT KNOW WHAT GOING ON.ANY SUGGESTIONS OR ADVISE GREATLY APPRECIATED.DUANE

92 thoughts on “4X4 PROBLEM S10 BLAZER”

  1. Now when you are talking about the cable under the battery on a chevy blazer that leads from the vacuum actuator to the front axle actuator silenoid (which is the electronic device on the front axle with the two wire plug. Now what the cable does is it controls the drop arm in the front differential, it does not just control the passenger front it controls the entire front axle through the spider gears. Now as far as manually engaging 4×4 you pull and hold tension on the cable you can not do anything back at the Transfer case and control your drop arm!

  2. I have a 98 Blazer which I cannot seem to pinpoint this vacuum issue I am having. The heat controls do not function properly (only comes out the dash and defrost). When I re-connect the vacuum line by the drivers side wheel well, there is a noise that seems to be coming from the drivers side front wheel. Also, it sounds like the truck is rumbling going down the road. When I disconnect it, it sounds perfect. Not sure if the 4 x 4 actually works, but it sounds as if it is engaging…

  3. Ok so my 2001 Blazer has been having this problem of the ABS and Parking brake light coming on normally when i hit a bump…also it seems as if i have to change the brakes on a regular basis considering little to no use…im in the service and therefore drive the vehicle maybe 2 times a year for a period of 2 weeks and everytime i come home it seems im changing breaks because they have warped or are just falling apart…my mother uses the vehicle in the winter time and its hard to say how she drives it since im not around (id assume she is careful) anyways im currently in afghanistan and the newest news is that she smelt brakes burning when she last drove the vehicle and the dash lights are not turining off as they did b4…she may just be being paranoid in regard to the smell but im guessing its a bearing or something since last time i drove it b4 changing the brakes it would shutter heavily and veer to the left when i tried to stop…id like some type of input since ill have to fix it next time im home and dont want to get hussled by a mechanic, thnx

    Kyle’s reply

    Hello Guest;

    Unfortunately, it’s hard to say for sure, the ABS / parking warning light can be a number of things… I’m going through the same thing right now.

    Last week I changed both front wheel bearing assemblies as they are all one unit and contain the ABS sensors. This is what “everyone” said is the number one problem… it may be, but it wasn’t mine. The lights remain. Unfortunately, I couldn’t get it scanned at the time and opted to change the wheel bearings anyway as the vehicle has 270,000KM on it now and the bearings are rated for 128,000KM – 160,000KM — I figure I got the life span of them. ;)

    Anyway, since then I’ve had the vehicle scanned and found the problem to be the ABS pump/module or simple the connections. I should have written it down, but when it was being discussed with my mechanic, it wasn’t an option for fixing at this point (he figures around $1,000… I don’t know for sure as I haven’t looked to much into it). I don’t plan on going any further with it. The lights are on… if it bothers you, I’ll put electrical tape over it. ;D

    As for the parking warning light… I don’t know how much I buy the explanation I got from the mechanic I talked to, but “he said” that the parking warning light will just start coming on after the ABS light has been on for a while. Sounds like he doesn’t really know, so tried to BS me.

    As for your brake smell, from what I understand when researching doing my brakes is that the calipers are prone to sticking after a brake job. What I would do is drive the vehicle until you smell something and then stop, get out and put your hand on the wheels one at a time… even go as far as sticking your fingers through the spokes and feeling the rotors or whatever you can reach… you’ll know if one is extremely hot then this could be your problem.

    Hope this helps.

    Regards;
    Kyle

  4. currently working on my 03 blazer. mine starting banninging in and out of 4wd. sometimes the cable gets a crack n the insulation and will cause a little rust to get under the insulation. this will hold the cable from diengauging or engauging the 4wd.holding it in between 2 and4wd untilthe drive bangs it out or in. one thing you might notice is the vaccum accuator will be totally collapsed or disfigured (mine totally got crushed under the vuccum pressure). take off cable from accuator, then crawl underneath and loosen 15mm bolts where cable goes into transfer case. this will allow you to see if rusty water has ran from the cable to the inside the gaurd. the cable is dissconnected in the same manner it is disconnected from the vaccum acuator. and i had to order mine from a dealer,,good luck with that!

    Kyle’s reply;

    Good information there — Thanks!

    Kyle

  5. Hi I have a 98 blazer 4×4 that has had 4×4 issues for quite some time now…..about 2 yrs ago I replaced encoder motor…and the vacume switch on transfercase because it was bad….vacume actuator under battery was in good shape being the battery hadn’t leak on it…then after winter…it stopped working again….then replaced since the encoder motor was under warranty replaced it again and still nothing …and then the switch….could this be the tccm? When you press the 4×4 high you can hear the tccm relay click…but hear no noise from the encode motor….any diagnoses i can run through b4 a by a used tccm..

    thanks,
    Nathan

  6. If you have a MIL Malfunction Indicator Light) that is blinking, especially Check Engine ot Transmission, DO NOT DRIVE anywhere but a shop!

    The blinking indicates that damage is immenant!

    Especially the blinking check engine light.

  7. Same thing with my 97. So, chances are you have tranny fluid through the vac lines. The output shaft seal, between the tranny and tcase is gargage, and needs replacement. This causes the fluid to leave the tcase and through the tcase vaccuum switch and into the lines. Easy way to check, remove batt and tray, and pull the vac line off the actuator. Switch to 4hi and you should get suction. If you don’t, cgange the tcase vaccuum switch( easy job) and might as well replace the vac line. Then. Check actuator for tear, and should move when 4hi is presses. Then it pulls a cable to the front diff, try to pull to cable by hand and see in it engages. Have fun

  8. Trying to replace the front, driver wheel bearing on my 2000 Chevy Blazer. I can’t get the hub to slide off the axle. I’ve even tried a hub puller with no success. I’ve done this repair before with no issues. Everything thats supposed to be out or off is (bolts, caliper, etc.). Any ideas?

    Kyle’s reply;

    It’s hard to say without being able to VERIFY that you have everything off/undone that needs to be. The hubs are pretty straight forward — I have done both front hubs on mine with no problems (actually, twice on the passenger side as the NEW hub failed in like 2 months).

    So, the hub won’t come off the axle, or it won’t break free from it’s mating surface? If it’s the first, then that means you have already broken the hub free, no? If the axle won’t come out (you do have the large axle nut off, right?), then put the axle nut back on so the threads are not exposed and give it a good couple of whacks with a good sized hammer (a 2 or 3 pound sledge works well as it has a nice size head so you don’t hit things you don’t want to).

    Good luck!

    Kyle

  9. Hello Kyle
    I have a 1995 chevy blazer LT with 4 wheel drive. When i press the 4 low the light blinks on and their is a thump like sound under the truck. But the light doesn’t stay on and when you puch thr 4 hi it does stay on and the thump also occurs but the 4 wheel drive doesn’t work. Whay could it be I’ll check the connector on the module on the passenger side or do you have an idea what i could be thanks Austin

    Kyle’s reply;

    Your description of your problem sounds like a hundred others here…there is tons of information here for you to get started. All you have to do is read.

    Kyle

  10. We just got out first four inches of snow here in central PA and I pushed my 4hi button and got nothing. It worked fine last year. When I put it in neutral and push 4hi, all of the push buttons (2wd, 4hi and 4lo) will blink like six times. Is this some type of code? It will only do the blinking thing once. I like this forum and I’ve got some good tips. I’m gonna check the vacume lines now since it seems like the easiest thing to do. Thanks in advance.

    Kyle’s reply;

    If the blinking is a code, I’m not aware of it.

    Good luck!

    Kyle

  11. Hey Guys I have a 98 sonoma and the dame thing dose not
    Go in to 4 hi. Can i just pull the cable under the batt
    and Manuly put it in 4×4 or an easy way to do that?

    when in nutral and i press the button you here a
    clunk noise and the botton on 4 hi stays on. But it is
    NO lock in. Its like you put it in HI and low back in forth over and over and maybe it goes in for a little and then kicks out. I would just rather Manuly putting it in. HOW???

    Any way Jesse Thanks

    Kyle’s reply;

    Pulling the cable under the battery will only engage the passengers axle. If the 4WD system is not working to begin with, engaging this axle will do nothing.

    Sounds like the fork that moves your gears in the front differential may be your problem.

    To manually put it in 4WD, get under the truck and disconnect the encoder motor. Once you remove the encoder motor, you should see a “shaft” (for lack of a better term) coming out of the transmission… that is what controls your 4WD. I can’t tell you which way is which as I’ve never done it… but one way goes 4HI, one way goes 4LO and the other is 2HI.

    Good luck.

    Kyle

  12. there is a recall with the abs malfunctioning on the four wheel drives, wouldnt hurt to see if your truck is covered

    now for my problem…

    can you tell me how to get the 4wd actuator cable out of the transfer case.. removed the three bolts holding it but cant get it out … i know this thread hasnt been used but im hoping its still checked

    Kyle’s reply;

    Thanks for the info — I will check it out.

    As for your problem, sorry, I’ve never removed a cable so can’t answer your question.

    Regards;
    Kyle

  13. Hey! Mine are doing that too. I don’t know a soulution but i can tell you my mechannic said it’s no big worry. I took it in for the first brake job ever at 230,000 kms and I thought that would fix the lights on problem when he ran it over he said it was some computer fault thing, but said not to worry it is still doing it’s job simply sending an error code. I forget the name of the part but he said it was around 500 buck with labour to change it and make the lights go out… I am saving money and thinking if is worth it… SO if anyone has that part name or number try and post it up so I can find a used cheap one and all of us can stop starring at red and yellow lights.

    Thanks

  14. We have a 97 Blazer and last time the Brake light(parking brake light) came on, I did everything you can imagine to try and make it go away. Then, after noticing that the truck was pulling I removed the rear drums, and found the problem. The auto adjusters for the rear brakes were stuck solid, and the brakes were no working at all in the back, after replacing the whole spring assembly and shoes then re-adjustusting the rear brakes, the ligh went out and the pullin stopped.
    I suspect the smell your mother is gettin is from the excessive load on the front brake pads du to the rear not working anymore, eventually the front pads will wear out completely. I suggest if ya replace the brakes again, do all four wheel, and replace the rear spring kit, then readjust the back brakes. If the rear ones are not adjusted the light will just continue to stay on and wear out the front yet again….Hope this helps.

  15. there is a vaccum line right down by ur brake pedle there is a clip that run defrost i have a 2000 blazer it did the same thing

  16. Mechanic wasn’t BS’ing you. My brake warning light also came on after the ABS light was on for a while. What a great way for the stealership to get you in for service. Just to note, my Blazer stops on a dime, no brake problems at all. I’m glad the ABS isn’t working anyways. If one wheel slips the ABS kicks in and send you right into the intersection, even though the other wheels have traction.

  17. I have a ’00 Blazer 2Dr. when 4x is engaged front diff bangs in and out as soon as I start driving any ideas?

    Kyle’s reply;

    Take it to a mechanic?

    Kyle

  18. Hi guys , this front end with the vacum and cable to engage the front axle will not do anything unless the front driveshaft will turn.if the transfer actuator motor is stuck,whitch will happen sometimes,the front driveshaft will not turn and it won’t matter what you do with the cable running to the front diff.so if the front shaft is turning and you pull the cable,this should engage the front wheels,if they dont there is a problem inside the front axle.

  19. This weekend headed up to the snow, all was fine the last weelend but this time, my heat and air controls didn’t work and when needed my truck would not lock up in 4X4.
    I have a Manual Shift lever not a button, the Wheel diagram would not light up showing it in 4X4.
    Thanks to all the comments I found that the Vacuum line for the 4X4 and my climate controls all come from a Ball vacumm canister mounted to the hood driver side back at the fire wall. There are several tees attached to the canister, I found the lower one had pulled loose from the Tee, hooked it back up and all was back to normal.
    problem is when the hood is opened the canister is lifted and can pull the same line out, I had trimed the line a week prior when I noticed it was dried and cracked at the end. One inch will do you in.

  20. I have recently bought an 01 LT Blazer 4×4. Had to do a good bit of maintenence to it to get it running right, but my main issue is now this: When I go to lock it into either 4 HI or 4 LO, I hear the diff lock in, but while in sand which I have found is the best place to test 4 wheel drive, I get no action from the front tires. But in reverse, they lock in just fine. Now another thing is that the lights on the push buttons never stop blinking as if it never actually locks in, but from the sound, I know that it has. ???????

  21. Kyle,
    I’m new to this forum, but I’ll start by applauding your last statement posted.
    I’ve owned 6 Chevys (S10 Pick-Ups & Blazer), loved them all!!!!
    Thanks for this forum, I’ll try all suggestions posted & get back to you…

  22. The problem I am having seems to be with the 4 wheel drive. When driving in 2wd, the passenger side front wheel has a loud mechanical whirring noise, related to speed, there is some kind of friction slowing down the vehicle. I checked rotors caliper for rubbing, they’re fine. Second thought was wheel bearing but was skeptical because That wheel bearing has less than 5,000 miles on it. Put the truck on jack stands and put it in 4wd. Front axle not engaging. the 4wd lights in the cab work, can hear relay click, can hear transfer case engage, but axle is not turning. Front wheels do not spin freely in 2wd or 4wd while on jackstands. They are hard to turn by hand. However, even though axle is not turning can still hear the noise when in gear and in 4wd. When I apply the brakes, the noise stops with the wheel. (which isn’t even turning??) The noise is not coming from the rear, there is no noise when the truck is in 2wd, and the truck is on jackstands. The noise is only in 4wd or when the front wheels are in motion in 2wd.

    If anyone has any ideas what to check next I would appreciate it. Going to check vacuum lines now, after reading other posts, but I fear my forks in the front diff may be the problem :(

  23. narrowed it down to the fuse/relay box under the hood. Changed it with one from a salvage lot… worked fine for a month, then failed to start again. Changed box again..sprayed all contacts with cleaner..changed START RELAY with brand new one.. One month later..fails again!
    I am also having (very rare)ANTI-THEFT irregularities
    ( lights & horn flash for no reason..then quit!)
    SUSPECT: on again / off again anti-theft circuit short
    disables starter! ( let it sit over night..& it
    starts in the AM & works for another week or so.
    Q – Can I find & remove the anti-theft control module w/out creating new problems??? MAYBE ! that’s the problem?

  24. I can be driving along and push the pedal and it is solid, no brakes. If I pump them several times they usally start working again. Some times I have to jump on them. Then the front end goes all over the place. After that every thing is normal, until it happens again.

  25. Hello im actually trying to help my sister out her 97 blazer is having 4wd problems, the button will start to blink to engage the actuator and then after about three blinks it seems to blow the fuse located in the drivers side end panel of the dash? any help on what to look at would be great thank you

  26. OK; got the Blazer back from the shop. You were RIGHT ON when you said that it was coincidental with having installed an amp. As an FYI for you and your readers: They diagnosed the problem as a bad bearing (driver side, front). They said the reason the vibration went away when turning left was because the weight of the Blazer shifted to the right side. Apparently the bearing assembly also has ABS sensors, so it cost US$230. With labor, an alignment, and an oil change, cost about $500. That was the bad news. The good news is that they fixed it. So, lesson learned: problem caused by newly licensed teenage son. Translation: doesn’t care about how fast he goes over railroad tracks, speed bumps, or pot holes (“since it’s a 4×4, shouldn’t it be able to handle that Dad???”)

    I will continue to read your excellent blog!! Thanks Kyle!!

    Kyle’s reply;

    Hello again, Kan.

    LOL! Teenagers, eh? Well, can’t say I haven’t been there and done that! :)

    Glad you got your problem resolved. Thanks for coming back and letting me know what the problem was, I’m sure it will help someone else out at some point.

    I actually think I have to do the same thing… I’ve just picked up a small vibration in the front end AND had the ABS light come on. Hmmm… a common Blazer problem me thinks.

    Regards;
    Kyle

  27. You can ignore/delete my submission from last night. I found out that cable coming through the firewall under the glove box was the antenna cable. I also removed the kick panel to find the amp’s power cable butting right up against the TCCM’s cables, which got me worried. But I tested everything and, except for the 4LO problem, everything seems to be working OK. I just still have that rubbing/vibration noise. I decided to take it to a local shop. Thanks for all the good info. I bookmarked your site.

    Kyle’s reply;

    Hi Kan;

    Hmmmm… sounds like you have an interesting one on your hands! Personally, I wouldn’t think that running your amp/speaker wires would cause the problem that you describe, but I’ve seen stranger things happen!

    Unfortunately, the only way you’re really going to tell if that’s the case is to remove the wires and see if it goes away (I know you’ve taken it to a shop now, so that point really is moot).

    Other than that, I would suspect that the rubbing/vibration that just started after your wire routing is coincidental.

    I really don’t know what to tell you, but if it were me, I’d jack the front end up and check the front end parts (tie rods, ball joints, idler arm, drag link, etc.). I’ve replaced the drag link, idler arm and upper ball joints on mine, but that was due to a loose front end (drifting) rather than a vibration/rubbing. Basically, I jacked up the front end, grabbed the tires (one at a time) top and bottom and “wiggled” to check for excessive play. Then grabbed them front and back and wiggled again. It’s helpful to have a second person to do the wiggling while you get under the vehicle and watch the various parts for movement. If things are tight, everything should move TOGETHER just slightly (depending on how hard you’re wiggling the tire). If the movement is seen in one part, but stops at the next, the joint/connection between the two parts is the problem. I’ll give you one last tip regarding this… if you take your vehicle in for an oil / lube job MAKE SURE they are actually lubing your vehicle! I took mine in for probably 5 or 6 oil changes before it was noticed that the shop was not lubing my vehicle. I’m pretty sure that was a major factor in the wearing of my front end. Long story short, I do all my own oil changes/lube now and only took it in because of the tires I bought… they were rotated and balanced every 10,000KM for free, so it was worth it for an few extra dollars for the oil change while I was there — ya just gotta watch ‘em like a hawk and make sure they do what they’re supposed to be doing.

    Good luck with your problem and please let me know how you make out.

    Regards;
    Kyle

  28. Okay! My uncle was suppose to get my original transmission rebuilt, but I found out that he had it replaced with a junkyard transmission. Ever since installation I have been having various problems. I tried to engage my 4 wheel drive hi. The light is on but when I push the gas, I hear this very loud banging noise as if the wheel is going to fall off. When I stop accelerating, the noise stops. When I put it in 4 wheel drive lo the light blinks. When I put it back in two wheel drive it works fine. I don’t know if it has anything to do with it but since this has happened, my ABS light also came on. What could be the problem because I was thinking that maybe he put the wrong transmission in and not to mention when I put my car in gear, the light that comes on to show you what gear you are in does not work properly. For example it will not highlight in neutral, drive 2, and delay highlighting in park and drive.

  29. I own a 1999 Chevy S10 ZR2 with a 4×4 problem – it doesn’t work. 4Hi doesn’t seen to do anything and it slips out of 4Lo right away. When I push the 4Hi button, everything seems normal. The light on the panel works fine. I hear the click under the glove box, I hear the transfer case motor shift, but the 4×4 doesn’t engage. I first assumed it was a vacuum issue, so I changed the actuator switch on the transfer case and also the actuator under the battery (when I pulled the actuator, it was filled with oil – any idea how that happened?) I also blew out the line that went from the actuator back to the actuator switch on the transfer case – there was oil in that too. Still doesn’t work.
    So I put the entire truck on stands, getting all four wheels off the ground. I started the truck in 2×4, back wheels spin like the should. I push the 4Hi button and front tires don’t move – even though everything sounded like it switched into 4×4 just fine.
    So with the engine still running and still in 4×4, I get out and look underneath. The front drive shaft is spinning at the idle speed but isn’t turning the wheels. This is leading me to believe that the front differential is shot. Is this so, or am I missing something??
    The blower inside only works on the vent setting. When you switch it to floor or windshield, nothing changes. Could this be linked to the fact that there was oil in the actuator?

  30. Kyle, you are my favorite person today.

    My wife drives, you guessed it, a 4×4 Chevy Blazer.
    She is a rural carrier for the United States Postal Service.
    She’s got 356,000+ miles on her current truck, and drives about 120 miles a day.
    She’s also got her father’s values.
    “Drive it ’til the dome light drags!” is her motto.
    She called me yesterday at work, during a snowstorm here in good o’l Illinois, and said her 4-wheel drive unit was not working. She had just been pulled out of the ditch by a farmer for the 8th time that day. She bought a spare Blazer with low miles for $4,000 last spring, and I thought it was high time to swap ‘em out.
    Before leaving work, I did a search for solutions to problem, and your website came up first.
    I am no mechanic. I can do the work, and have rebuilt motors, but I don’t have the patience for it.
    I checked the diaphram on the vacuum switch under the battery tray and it had a tear in it.
    Swapped it out with one from the spare truck, and TA DAAA!
    She’s back on the road today, for $0 and about a half hour of work!

    Thank you so much for supplying this information to the working people trying to hold on to what little they have!

    You DA MAN!
    Miccol

  31. I have a 2001 gmc Jimmy, I have just recently tried using my four wheel drive. Used it one night to go mudding, and now that we are getting snow I am having problems. Use to when my truck was in park I could hit my 4 hi button and it would lock in just fine, now if my truck is in park my four wheel drive won’t do anything. If i put my truck in neutral I can get it to lock in 4 low, but I can’t get it to lock in four hi for anything. I have my torsion bars tightened so that I can clear 31×10.50×15 could this have anything to do with my truck not wanting to lock in 4 hi? Please send any suggestions to gmcwebb@hotmail.com

  32. 4×4 worked fine for start of winter season. Always came out of 4wd to 2 wd with very loud thud as if I just hit a 6″ deep pothole. So I tried not to engage 4×4 too often. But 4×4 stopped engaging all together. Delivering the mail in Indiana with no 4×4 has me spinning.

  33. someone told me to check the fuses, but still not working. also have the same proplem as the guy “Kirt” in that my dash heat won’t transfer from face and defrost to heating your feet. also my truck doesn’t warm up much past 150 degrees, so it never really warms up.. any ideas on how to fix this?

  34. I agree with Kyle, I myself own a 95 4×4 blazer and I have owned it for four years now. I may complain now and then about it, but so far it’s the best vehicle I’ve had or owned for that matter. it gets me from point A to point B and everywhere else.. If and when I decide to get another vehicle, it will still be a Chevy blazer. there’s nothing like them,in my opinion. another thing, I am not a kid, I am 61 years young (a kid at heart)! oh and good luck with your son’s decisions about how he drives or repairs HIS blazer.

  35. Hi Jeff;

    Sorry, I’m not going to be much help with your questions… I’m not a mechanic and can only give you information that I have learned while fixing my own vehicle. Unfortunately, what you describe I have not encountered.

    As for how the 4×4 system works, what is it you want to know? It’s pretty basic actually. The encoder motor engages 4WD within the transfer case which drives the front differential. The drivers side wheel is always engaged at this point and the passengers side wheel is engaged via a vacuum controlled cable (actuator – lunder the battery). There are no “hubs” (so-to-speak), not in the way that you use to see on the older systems where you’d have to lock them.

    The only thing I can think of is to get it up on a hoist, put it in 4WD and listen to it. Hopefully, you’ll be able to pinpoint where it’s coming from.

    Good luck!

    Kyle

  36. I found the problem…it was the U-joint on the front drive shaft.

    Thanks for the info on the 4×4 system.

    Kyle’s reply;

    Thanks for the update, Jeff — glad to see you got your problem solved!

    Regards;
    Kyle

  37. why oh why, when all of you know these vehicles are rotten to the core and need constant repair and gasoline…do you continue to own them? yeah i agree they’re cool lookin and represent “devilish kids at play” but really, seriously, is this all you have to spend your money and time on. it sounds like most of you and my son included want to be your own mechanic and that’s probably cause of the cost of almost daily repair…but what part of giving your money away do you not understand? i don’t mean to bad mouth anyone but i am so tired of my son wanting to use my car cause his 4×4 is back in the shop. this time it’s more serious than other times. he’s even had a new engine put in but the front end problems, rear end problems, 4 wheel problems and everthing else in between is robbing his little family. it’s just a maturity thing i guess. do you enjoy having vehicle problems that you can’t find answers for?

    Kyle’s reply;

    Who says these vehicles are “rotten to the core”? You? Typical.

    I’m 40 years old — I don’t give a shit what you or anyone else thinks “is cool”. My Blazer was a work vehicle and it was driven hard — for 5 years.

    Actually, the Blazer was one of the best vehicles that I have ever owned. Other than the 4WD problem, I haven’t had any other problems with the vehicle. I just sold it with over 300,000 KMs on it and it passed a legal safety and eTest. The ONLY thing the mechanic could find wrong with it was a license plate marker light. In fact, I sold it to my brother who will continue to drive it (which I wouldn’t do if it was “rotten to the core” — I’d sell it to someone naive, like your son).

    Unless you have lived in a bubble and don’t possess a drivers license, you would understand that if you drive a vehicle it IS going to need maintenance and repair. If you use your dishwasher, it IS going to need maintenance and repair. The Blazer is not unlike any other vehicle. Sure, there are going to be some that were built on a Friday and may have some issues (again, not unlike ANY other vehicle), but on the whole, the Blazer is a dependable vehicle. Yet you come here and read a few stories on a specific topic regarding problems with SOME Blazer 4WD systems and all of a sudden they are “rotten to the core”. If you visit ANY forum for ANY make of vehicle you will find that they too talk about specific problems with that make and model of vehicle. Does that make them “rotten to the core”?

    I also own a Dodge Nitro — a vehicle that is not given a great report by Consumers Reports, yet I have owned it since new (just over 3 years now) and have not had one single problem with it.

    I also own a brand new GMC Yukon XL — I had it back to the dealer in the FIRST MONTH for an idler pulley replacement because it failed. Does that make my Yukon “rotten to the core”?

    As for being my own mechanic — absolutely. Why? Because I can. Because I have the ability to do something that will save me a ton of money by not dishing it out to mechanics charging $75 an hour. You have to think about things a little more and analyze them. Think about this — my mother makes all kinds of things — sewing, knitting, needlepoint. She makes drapes, clothes, furniture coverings, etc. Why does she do this? Because she can. Because she has the ability to do something that she doesn’t have to pay someone else to do. Could she afford to buy these things? Absolutely. Can I afford to take my vehicle to a mechanic? Absolutely. But why?

    There comes a time when you have to sit back and evaluate your vehicle. If your son really has had so many problems with his Blazer, then I would have to say your son should have been smart enough to get rid of that vehicle a long time ago. If your dog bites you, then pees on your carpet, then rips up your furniture… you get rid of the dog. You don’t keep taking him to therapy, thinking it’s going to get better!

    Regards;
    Kyle

  38. I have had this problem three times on my 2002 ZR2 the four wheel drive switch sucks fluid out of the transfer case blowing the switch causing your 4 wheel drive to engage part way. Mine was covered under an extended warrenty but did run about $1000.00.

  39. I agree with Kyle’s reply, and would like to add to it.
    You may also want to think about your son’s driving habits. Anything that can be “made”, can also be broken.
    Another thing to consider, if you are “constantly” needing to take ANY VEHICLE to the mechanic, it may be time to find a new MECHANIC. I have a close and trusted friend, that sells parts to repair shops. He has told me of some of the “dishonest” shops, and the methods they use, to keep their customers coming back for more.
    Another good reason to learn to fix it yourself.

    regards

  40. i have a 2000 4 dr 4×4 blazer and i hear a relay or switch clicking in my passanger floor board. but when i hear it click about 6 to 10 times in a row my service 4×4 light comes on and my actuator tries to engage the 4×4. even when the keys are out of the car. i have filled all the differntals transmission i put a new battery in it i pulled the fuse but it still did it. i need help.

  41. Sounds like your injector or injectors are plugged and starving the engine. try a can of sea foam in the gas tank.

  42. I realise his question was a while ago, but to anybody else who stumbles across this I thought I might add, given his symptoms, check the catalytic converter for flow. A plugged cat can cause loss of power, trouble starting and overall lack of performance. Before you spend all the money on a tune up, etc.

  43. Yes my name is kyle and I have a 1999 chevy blazer 4×4 and i have the same tccm problems like everybody else but my only problem is that i need the new 32 pin femal plug and the 4pin female cause my tccm is in working condition. I can’t find then plugs and wires anyplace :) i know what are odds there. My second problem is that if my blazer sits for a few days and doesn’t get started it doesn’t want to start and you have to spray starter fluid in the vac line on the throttle body and also with that when you go to give extra gas for say highway or pulling out infront of a person the blazer falls on it’s face. I have replaced the plugs twice, wires twive, coil pack twice, and had oil change and tranny flush(and tested) fuel pressure is good. no servive engine light or service 4×4 either! please help me somebody!

  44. I would be willing to bet that your mass air flow sensor needs cleaning. Had the exact same prob with mine. Its a simple fix. Buy the cleaner at any parts store. They will be able to tell you where the sensor is. Really simple takes about 15 mins.

  45. mine did the same and it had no codes up so i put a new mass air flow sencer on it and it runs great now hope it will help u

  46. My blazer had the same problem. As is everybody else. ets just not buy these. My problem ended up being two things. One someone put the wrong fuel pump in my car. their for it not getting right furl pressure. Also the problem was that the spyder injection system was clogged and not spraying in all 6 cylinder. So had to replace that. maybe something to look into on yours. lol

  47. hi kyle it sounds like if its an automatic your tourque converter may be locked up …..or your throttle positioning sensor could be bad

  48. hey i have a 1996 blazer but my abs light on wront go off we put all new braks and calibers on and bleed them nothen but fluid and i still have half brakes it feels like it air idk wats wrong with it.

  49. hey i have 1996 blazer my abs brake light wront go off we put all new brakes and calibers and still have half peddle and we get nothen but pur fluid out of it every thaing new still feels like their air in it

  50. I hear this rum rum rum nois when driving so I pulled tire of check hub assembly it’s fine bearings fine put it back together took a ride put I 4 wheel drive not workin it use to work fine jacked it up spun tires forward but hand I could hear the nois sin it backwards no noise is it my transfer case ? When I push button for 4 wheel drive it goes away but comes back

  51. Hello,
    I need to pinpoint the problem or parts needed to fix. I am a mechanic. I have been out of it for years but actually worked at several shops and worked on many cars. So I do all my own work but need a bit of help sometimes to pinpoint problems. I recently replaced the transmission about 20,000mi ago. I changed the passenger side hub assembly a couple years ago and just changed the drives side hub assembly a few months ago. So, my problem has two symptoms. One, a metal creaking sound when I press the brakes and the weight shifts to the front of the vehicle. It will even sound like a creek pop when I come to a complete stop. I can make it do it if I step on the brakes and let off over and over it will creek pop, creek pop. The other symptom which didn’t happen till I just put new front break pads on, when stopping from high speed at about 30mph or less the drivers wheel wobbles. I let off a bit to releave it some and then below 15mph is stops. When I changed the brakes, the drivers was almost bottomed out and the passenger still had several hundred miles left on them. Possibly from the wobble it ate into the brakes. I just need to know what I should attack on this. And what parts to go pick up and replace on the front end. One other thing it does seem like when I jack up the car the bottom of the wheel seems to point inward and seems to be doing it a few centimeters when it’s just sitting there after driving but It’s so slight I keep thinking I’m seeing things but it could be. Thanks for reading this book! Hopefully you can help me out here. Thanks, Bret :-)

  52. I have a Chevy Colorado z71 ls I recently installed a four inch torsion lift in the front and 3 inch shackles in the back to fit some 33s being neive I decided it would be funny for a day to crank way down on the torsion bars to where I got around six or so inchs of lift in the front. I drive it around town and all was good. Not taking into consideration the incredibule angle the cv half axles were sitting at I took it on the highway for a short stint. Needless to say I blew out one cv boot and stroke the axle on the adjacent side. I know it’s broke because I pulled the hub assembly here recently to replace some broken lug studs and the cv shaft was by look and feel obviously seperated at a joint. I plan to replace the cv half axle hear soon but my 4×4 still works after a few minutes after engaging my question is is that because the limited slip is engaging to the other side there for getting power to that wheel when the limited slip was engage in the opposite direction and no power was getting to the front wheel due to the busted cv Hal axle. Or is there another problem I should be on the lookout for

  53. Bret,

    Classic symptoms of bad ball joints. Replace them if they’re OEM, there’s been cases of ball joint separation and the whole thing falls apart while you’re driving!

  54. I have a problem with the 4×4 on my 2002 gmc. sounds like a scraping noise in the front end. Used to clear up by shifting to 4×4 and back to 2wd. Is there a way to check the hubs(sticking) or the cv joints? Where can I find a diagram or explanation of how the GM 4×4 system works?

    Thanks

  55. I have a similar problem. i hear a roar from the front passenger tire and when i engage the 4wheel hi it goes away then when i put it back in 2wd the sound comes back. did u ever figure out what it was. cause im stumped. please email me back or post thanx

  56. Hi this might be too late but I believe the sound you are hearing is due to the actuator not fully engaging, perhaps the cable is corroded and or stretched or the vacuum actuator is leaking but either wy that sounds like what you are having a problem with, you can check it by jacking up the front end putting the truck in neutral and manually moving the actuator cable in and out by hand while having someone rotate the front wheels for you, if you dont fix that soon you will end up with damaged gears if they aren’t already and then instead of a new cable and or actuator replaced you will need to replace most of the front axle components, hope this helped, cheers ^^

  57. Hi Kyle… I googled on some words regarding my 1999 Blazer 4-wheel drive problem and came to your website. That was 3 hours ago!! What a great site! First off, let me say, I know you’re not a mechanic so I’ll try not to be one of those that just doesn’t “get it.” I don’t even know if I have a 4-wheel drive problem, so I’m not starting out on the right foot, am I? :-) Anyway, I have this rubbing/vibration noise that just started; can feel it immediately even at low speeds, almost like driving with studded tires; gets louder the faster I drive. If I turn the wheel to the right, same thing; to the left… goes away. When I touch the floor down by the accelerator, I can feel the vibration like it’s coming from under the hump. So I thought it was some type of differential, axle, or front wheel drive issue. I was thinking, “What might have caused this to start all of a sudden??” Well, just before this starting happening, my son and I installed a sub and amp in the back of the Blazer. We took off the dash so we could get to the radio (had to unplug the 2/4 wheel switch module); then we routed a power cable under the passenger side carpet (very close to the doors), under the passenger side kick panel (didn’t remove it at all; just slid the cable under it), then behind the carpeting on the passenger side, through a firewall hole we found (under the glove box area). That hole actually had some type of cable going through it with a small rubber grommet. The hole was barely big enough to fit the power cable through. We then pulled the power cable through the engine compartment, cable tied it to prevent it from getting in the way of anything, easily connected to the battery. I was thinking that the existing cable was related to the heating system, but maybe not?? In trying to troubleshoot this problem, I was trying to figure out what we might’ve done that would have caused this issue (not using 4 wheel drive at all these past few weeks). 1) Do you know what that cable might be? Would I have disturbed the 2/4 wheel system in any way? 2) The Blazer still picks up speed and drives well except for the rubbing/vibration now. Would having pulled out and put back in the dash switches or being in such close proximity to the TCCM caused issues? I also now notice (in testing it) that the Auto 4WD, 2HI, and 4HI buttons work, but that the 4LO button just blinks when pushed (in neutral). I have to push one of the other buttons to get out of it. I do not know if this was an issue before all this started (I never use 4LO). Anyway, based on your experiences, I thought there might be something I mentioned that might ring familiar to you. I’ll try the disconnecting the battery trick 1st thing in the morning and will keep you posted. Thanks, and GREAT BLOG.

  58. ok sooooo 2000 chevy s-10 4wd zr2,,,,,,
    4wd drive would not work nor would lights on dash come on or change from 2hi to 4hi or 4lo. also seem to lost some vacuum in the dash regarding heat and dash vent air. they wont switch from floor heat to dash air.
    rewired wires to TCCM. bipassed the corroded harness. had some response. now the lights would come on the dash and i could hear the TCCM “click click” but lights would flash and go back to 2hi. 4wd never did engage.
    changed the vacumm thing under the battery and also changed the actuator switch on the transfer case AND changed ALL vacuum lines.
    cant find any bad fuses either.
    still nothing. any ideas?

    Kyle’s reply;

    Hi Kirt;

    Wow — sounds like you’ve done everything that I would have suggested. Accordingly, the only thing I can think of at this point that you haven’t done would be to change the encoder motor.

    I know you’ve changed all the vacuum lines, etc. — but have you actually tested for good vacuum?

    If you have someone to help (you’ll need them in the vehicle to push buttons while you’re under it with a volt meter), you could grab the schematics from the first post and test the wires at the encoder motor. Test the main 12V leads to make sure you’re getting main power to the motor, then test each of the 5V signal lines to make sure you’re getting the signal to change modes at the encoder. If everything is good, odds are your encoder motor is shot.

    Oh, BTW, if you haven’t read it in one of my posts here, there are fuses UNDER THE HOOD that you might want to check as well.

    Good luck and let me know how you make out!

    Regards;
    Kyle

  59. I am a girl and I don’t know anything bout cars but I had same problem with lights on dash. Also when I pressed the brake my reverse lights would come on. My husband found out that my tow package wires had been cut and were fused with other wires. They changed some wires and I’ve never had the problem since. Just a thought.

  60. SOunds like the same problem I have with my 2003 s10.
    I cleaned the grounding point at the fuse and relay box under the hood. The grounding point farthest front of box.
    I had alot of intermitting issues including the 4×4.
    After I cleaned it, everything started working again!
    who knew?

    Jeff

  61. When I backed out of the drive way the right front wheel made a sound like metal hitting metal, very loud and ruff. I thought the wheel was going to fall off. I drove it just a little bit and every right turn it would make sounds and you could feel it in the ride. My son noramlly drives this car and it has been doing this for some time, but sometimes stops for weeks at a time.????? any ideas? thanks Michelle

    Kyle’s reply;

    Hi Michelle;

    Assuming the problem IS coming from the passenger side front wheel (sounds can be very deceiving) it could be a number of things. It’s difficult to say if the sound goes away for weeks at a time, as well as not knowing what happened prior to the noise — for example, was the vehicle put in 4 wheel drive and then the noise started?

    If I had to guess though, I’d say wheel bearings, a sticking caliper, CV joints or maybe a front U joint as our last poster, Jeff, reported.

    It could also be something as major as the transfer case (mine made a really loud and rough bang when I had problems with the shifting from 2HI to 4HI — sounded like I ran over a garbage can). The thing with that though is that the sound didn’t go away.

    Either way, I’d have it looked at ASAP as front end problems can be quite dangerous (and if it’s a transfer case problem you don’t want to destroy it by letting it go).

    Good luck!

    Kyle

  62. If its on the transfer case it will be on drivers side at the top rear. One is a breather linethat should be zip ties to tranny tube . one to your vacuum can 4 the 4 wheel drive and the last one goes onto the intake. If you take the nipple off the t case make sure it goes back on the same way it came off it can fool ya if you don’t pay attention. I learned that the hard way lol. If anyone has to change a heater core on one have fun

  63. I have a 96 chevy s10 blazer 4×4, my front axle wont engage. I can hear it go in via the transfercase but front tires wont turn. The light comes on so I dont think it is electrical. I did locate the vaccum actuator under the battery but there was no vacc line attached to it. I have no Idea where the source of that vacc comes fron is there any way you can coach me through it or send me a diagram. The actuator itself looked to be in good cond. I just noticed that the nipple on the actuator was open(no hose to it.) I would apreciate any assistance.

    Kyle’s reply;

    Hi Randy;

    I am not sure where the vacuum line comes from on a ’96 Blazer, but I have only heard of it coming from two places;

    1) the vacuum comes off the drivers side manifold and goes to a reservoir (also on the drivers side), then to the vacuum switch (center firewall), then to the actuator (under the battery) — this is where mine is located. Here’s what the vacuum switch looks like –> http://kylestubbins.com/files/blazer_vacuum_switch.jpg

    2) the top of the transfer case (I believe that’s what one of my posters had said… it was that, or on top of the transmission — I can’t remember exactly, but it shouldn’t be too hard to find — follow the vac lines!

    Good Luck!

    Kyle

  64. i had a similar problem with my 99 sonoma. i would hear all the clicky clicky and the lights would stay on like they should but front wheels would not engage. same thing in 4 low. the vac actuator had a tear in the bottom of it so i replaced it thinking it would fix the problem but my front wheels still wouldnt engage. it turned out to be that the clip for the new actuator was defective and not holding onto the cable. i put the old clip on it and it works just fine now. something you might check.

    Kyle’s reply;

    Thanks for the information! Hopefully it helps someone out!

    Regards;
    Kyle

  65. look under the battery, GM had this great idea to put a vaccum diaphram where acid can drip and burn a hole in it. check this and possibly go to a junk yard and find another vaccum switch. Have someone engauge 4×4 while your under truck so you can hear the switch engauging to be able to find it. its right underneath on the tranny. this is a 400 -600 part new. if you have a hole in the vaccum diaphram,, use a bike tire patch kit to fix this..a little 25 cent fiix for you.

  66. i had this problem with my envoy 4×4 98 model,while driving i heard a slight grinding noise.it quit so i didnt sweat it.two wks laters it happened again but it was louder.i jacked up the driver side wheel,removed tire/rim,loosened the wheel hub nut.so it wouldnt be as hard to remove it when brakes are disassembled.see when i tore it down ball bearings fell everywhere,so i knew right then that was the prob.had to get wheel bearing hub assembly $100bux fixed it no problem…..hope this helps someone.

    Kyle’s reply;

    Hi There — thanks for the info!

    Kyle

  67. ok i just got a 1999 chevy blazer i put it in 4hi do to the snow the day i got it and now it will not go back to 2 hi. i get the clicking noise and the lights on the dash says it is in 4hi. can some one tell me a few things about the lay out of the drive system such as where is the actuator, the encoder motor and such plz email me back

    it seems like the 4×4 system is not very good in the blazers, but u have a problem with sometype of electrical systems with all makes and modles all i want to do is get mine fixed cause i really like it but husband wont let me keep it if it is goin to be a hasle plz help me at fire_frog_2005@hotmail.com

  68. I have been chasing a problem with my 4WD for a while. It turns out that I had a bad clip with my new valve. When I replaced it with the old clip it worked great. Thanks for posting this or I wouldn’t have found it.

    Kyle’s reply;

    Awesome! Glad that some of the info here was able to help you.

    Kyle

  69. Ok ! this is how you reset your 4×4
    Don’t start your truck, just turn the key until the lights in the dash comes on then,
    put your truck in “Neutral” then,

    if your truck was in 4×4 LOW, you got to press

    the 4×4 High first, wait five seconds then press the
    2×4 HIGH.

    If the truck was in 2×4 HIGH then, just press the

    2×4 HIGH.

    That should reset everything.
    It’s working on mine

  70. love your comment to the import guy. out of a job yet? keep buying foreign. i got my 99 blazer at 160,000 for $2000 been very happy with it , done a muffler,wheel bearing,u-joint, small price to pay for a reliable Chev. found your page when i googled blazer 4×4 light found a lot of good info. just went to the post office and it poped on when i turned the car on i use it maybe once every 2 weeks so it could be a million things gonna take it to my buddys dad hes building a 67 vette from the ground and hes got all them fancy computers so ill see what code pops up. awesome blog man.

  71. When I press the 4hi button on the dash it blinks a few times and then clicks on and the light stays on but 4wd does not engage. If I press 2hi it clicks and the 4hi light goes off but the 2hi light doesn’t light up. Same if I press 4lo, there is a click but the light doesn’t light up. The end result is the same…she stays in 2wd. Last month it was intermittent at best. The inside 4hi button would blink and click on but 4wd did not engage. If you drove forward and then put it in reverse and drove back in the drive, you could hear the transmission finally switch to 4wd. It doesn’t do that at all now. Any ideas?

  72. Kyle,you put it just perfect! From a very proud RED-NECK in the U.P of MICH!!!!!!!!

    Kyle’s reply:

    Happy to amuse! ;)

    Kyle

  73. I have an 02 Blazer and I too have this 4×4 problem of the front axle not engaging and the lights are saying it is. Solution – don’t buy anymore GM/Chevy garbage! No wonder they went bankrupt. It’s making POS quality garbage cars like these! Cheap plastic interiors and low grade quality mechanisms. Good thing I only bought this thing for $1500 as a 2nd car for the winter…no wonder they dont hold their value. As soon as spring comes this thing is getting rid of. I’m sticking to my imports.

    Kyle’s reply;

    Well, all I have to say is this;

    1) I drive for a living. I understand that vehicles need maintenance and are under constant wear and tear. The Blazer, other than some electrical problems with the 4WD system, has been one of the best vehicles that I have owned. I have almost 300,000KM on my 2003 and it still drives like the day I drove it off the lot. I haven’t a single complaint in regards to the S-10 Blazer.

    2) You get what you pay for. You bought a $1,500 car. Do you expect it do drive and be like a $15,000 car?

    3) When you’re out of a job, I don’t want to hear it. But hey, at least you’ll be able to drive to the welfare office in your import!

    Kyle

  74. I have an 02 Blazer also and I have this 4wheel problem of the front axle not engaging and the lights are saying so, i had it checked out and its not a electrical problem says a code reader.. not sure what to do next, anyone know?
    thanks
    Ethan

  75. Kyle, you are awesome. That was so funny. But so true at the same time. Hey Kyle, you rock dude. Keep up the good work.

    Kyle’s reply

    :)

    Kyle

  76. my fourwheel drive will not work, i was pushing the 4hi botton and the 4hi and 4lo blinking and then dropped into 4 lo, could not drive truck, bought a new transfercase acuator notor, had to manually switch trans into 2hi, truck now in 2hi, but switch on dash says 2hi, but i push the 4 hi button and nothing?

  77. Hey, I just came across your page and seems really neat. Anyways I have a problem and hope you or one of your readers can help me. I have a 2001 Blazer LT. First off my gas gauge wont work, when im driving it sits on ‘E’ so i never know how much gas i have, i’ve replaced the Fuel pump twice and still nothing. HOWEVER when i turn off the engine and lock the car the gauge jumps from “e” to 3/4 full even if i have little or no gas.. another issue is my 4×4 wont work it says its on 4HI but i know its on 2LO and when i press the 2LO or 4LO buttons nothing happens except for the relay making a ‘click’ sound and i dont know if this is related but when i make tight turns either left or right i hear a ‘thud’ noise and feel as if i was driving thru some bumps, Now thats only when i make SLOW TIGHT turns. i have had the transfer case replaced, u-joints replaced not sure if those problems are related…. can someone PLEASE HELP ME…….. im desperate lol

    thanks
    Noe

  78. My 1999 Chevy S-10 is making a rubbing/grinding in the front end and it increases with speed. It is not affected by the engine or gear. It softens when I go over and when I turn either way it seems to get a little worse. It would seem that it is affected by the overall downward force on the vehicle. It is coming from the center of vehicle (so it appears). I have had issues with running through brake pads in the past but they appear fine. I have replaced both front hubs as well. Could it be that the front differential needs rebuilding or just bad bearings somewhere in the front assembly. I don’t know if this vehicle is prone to differential problems or if there is a common failure elsewhere?

  79. i have 2001 chevy s-10 zr2 and i cant get my front end to work ill push the button for 4hi and 4lo and the light come on like the front ends workin and i hear the transfer case click in but the 4wd still not workin ive read the post and looked the the vacuum lines but i cant find the one on the firewall and there wasnt one under my battery tray so i took my skid plate off and found some vacuum lines there and one that the nipple for a vacuum line is broke but i have no clue wat it is any help would b greatly apprecited

    Kyle’s reply;

    Hi David;

    Sorry, I have no clue either as I am not a mechanic and can only give you the information that I have first hand knowledge of.

    Kyle

  80. hi, i have 1999chevy s10 pickup and my transfer case if engaging but my front end will not im geting Hi and Lo gear but my front wheels wont turn. i replace the acuator cable and the vacuume actuator. what could be my prb and i have checked the elctrical and hoses. could it be my hubs or cable still?

  81. hi there i have a problem with my blazer not shifting into 4wd here the click click and motor switching just not locking in could my actuator vale be bad nopt pulling cable in could you e-mail me a possible problem or fix .

    thanks Rob

    Kyle’s reply;

    Hi Rob;

    If the answer has not already been posted within the hordes of posts regarding the Blazer 4×4 system, then I don’t have the answer you’re looking for.

    Regards;
    Kyle

  82. Hi I have a 94 s10 pickup that has pushbutton 4×4. When driving down the road it has no lights on. But when stopped and in nuetral it clunks right into 4×4, so it thinks that it is in 4×4 but actaully the front wheels aren’t spinning. So i replaced the 4×4 actuator and the 4×4 pushbutton. But neither of them have seemed to be the problem. I don’t see any cracks or splits in my vaccum lines also. So can you tell me why it isn’t working?

    Thanks,
    Troy

    Kyle’s reply;

    No. I am not a mechanic.

    Kyle

  83. it sounds like the transfercase is working. but just remember 4HI is a on-demand thing and wont engage unless the rear slips but sometimes it will go ahead and shift. but back to tha question if the light is working and u replace both modual on the transfercase and the push button cluster thin there is a acsuwater under tha battery plate that a cable runs from and gose to tha front diff there could be a pin hole in it so check that i have tha same truck as u so if this works it might save me some trouble. lol

  84. Kyle’s reply: No. I am not a mechanic.

    Kyle

    Then why waste space with a reply that is useless???

    Kyle’s reply;

    Because I’ve stated MANY times that I am not a mechanic and people like you keep wasting my time asking me questions that they should be asking a mechanic.

    I post my own personal experiences here to help others that may have a similar experience. I’m not here to solve all your mechanical problems. If you can’t find the answer to what you’re looking for on my site, DON’T ASK ME FOR HELP ’cause I AM NOT A MECHANIC.

    Clear?

    Kyle

  85. The reason your s10 won’t shift into 4wd while your driving down the road is because it’s a clutch gear 4wd transfer and if your driving when you engage it your 4wd clutch is free spinning and doesn’t have time to engage.

  86. Hello every one I’m haveing an issue with my 1991 s10 blazer z code 4.3l v6 2 door 4×4. this issue seems to only happen. During times of the day were the temp and moisture change. During late morning to late evening. the engine dose not have mutch power, eats gass, and very doggy at low rpm. I’ve replaced the cap and rotor, regaped the plugs and checked resistence in the wires and there is no evedance of green and fuzzy also there is no dtc’s. But during the rest of the day the engine runs perfictlly normale. what do yall beleive is wrong?

  87. my 1998 blazer will just go into 4 wh and lo light blinks while driving down road. if i change to 2wh drive it stays untill i stop or shut vehicle off. i was told encoder motor was bad. thanks jim

  88. John,

    I had this exact symptom on my ’97 Blazer. The problem is that the vacuum switch on the transfer case has gone bad. Drivers side top rear of transfer case there’s three vacuum lines in a connector/grommet that connects to a part that screws into the transfer case. You can buy this part at any auto parts store. Transfer case vacuum switch.

    What’s happening is that the vacuum is trying to actuate the 4WD despite you not switching it on, because the vacuum switch is bad. So the growling noise is the fork in the axle trying to engage. Notice how it will stop when you slow gradually and reach about 10mph or so? With a ‘clunk’?

    It’s an easy fix, you can do it without even jacking the truck up if you’re skinny enough! :-)

    Jim

  89. Hi Kyle,
    I’ve read all your posts dating back to 2007 to current and have learned a lot about how my 4 wheel drive system works. Thank you sooo much for sharing what you know and helping so many people.
    I have a question that I hope that maybe you or one of your readers might give me a clue as to what to try next. My truck is making a a rubbing/growling noise from the passenger side front tire. I checked all the fluid levels, replaced the bearing hub. Still growls. I had a vacuum hose that was unhooked from the box inside the wheel well ( I must have accidentaly pulled it loose when I was changing plugs a couple of months ago)and hooked it back. I checked the vacuum lines, the diaphram under the battery (thought the cable might be sticking and not letting the axle fully release, the cable seemed to go through it’s full range of motion), the brake pads are in great shape, and it goes right into four wheel drive with no hesitation. As a matter of fact when I put it into 4 wheel drive the noise stops completely. As soon as I put it back into 2 wheel drive it starts right back up. I’m fairly mechanically inclined and determined to try to fix it myself to save the money and just so I will know how to do it. I even laid out some bucks last night to buy a 3 volume set of shop manuals for the 2000 S-10 in hopes that maybe I can find an answer on what is causing the noise. Once again thank you and anyone else who would have any input on where I should look next. John

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