Chevrolet Tahoe Suburban 4 Wheel Drive Indicator Lights

aasikesaasikes Member Posts: 1
edited August 2015 in Chevrolet
I have a 2003 Tahoe, and my indicator light changes from 2 wheel drive to auto or to neutral without me pressing any buttons!? Anyone else have this problem? I hope it's not expensive to fix :-)

See Also
Fixed My Blinking Push Button 4WD Problem


  • ugamattugamatt Member Posts: 1
    I've got 55k miles on my Tahoe and indicator lights for the 4 wheel drive will come off sometimes when I start the car. Other times it will already be set in 4 wheel low. Obviously I need to get it serviced. I'm just surprised that happening with only 55k. Something I should cautious about when getting it fixed?
  • jlobatojlobato Member Posts: 1
    I have a 2002 Chevy Suburban 3/4 ton. The "Service 4X4" indicator light stays on and my vehicle is stuck in 4 wheel drive. Any suggestions?
  • blueeyes6blueeyes6 Member Posts: 7
    I work in the service dept. at a chevy store,
    I would tell you to have the truck taken to a dealer never you :sick:
  • peatropeatro Member Posts: 1
    The fan switch on my 1999 Tahoe seems to work only when Hi is selected, although there are occassions when dropping down to Med-Hi that fan still runs and sounds as though there is no change in fan speed. There are also times the fan does not run when Hi is selected as well......
  • fire305fire305 Member Posts: 2
    I have a 2004 Suburban. When I start my suburban, it will be in 4L or 4H or the red light N, or no indication at all. My Service 4WD light will come on after a while. Sometimes it works fine. I have read lots of fixes, like a ground wire no being connected, the switch needs to be replaced, the sending unit is bad, and finally, a computer chip is messed up. A friend of mine had a computer chip replaced, and that fixed his....of course, his truck was still under warranty... mine is not. If anyone has had any luck with a certain type of fix for this, please let me know so I can go to the dealer with some knowledge, so help save me a little dough. Thanks.
  • chevy4playerchevy4player Member Posts: 1
    I own a 2003 Chevy suburban and have the same problem with the 4wd and I found out that in times you need to get it working you can pull the fuse ("TREC" all wheel drive module) from under the hood and wait 15 seconds and install it again. This is the fuse for the all wheel drive module. Do this when the truck is running and it should activate the module to get everything working again. Living in Wis. you need 4wd to get around in the snow.
    I was told that the module does not sense the power so it does not turn on. now it been working fine for 3 months now and it did not cost me anything. This not a fix all solution but it worked for me. right now
  • jacktanner0jacktanner0 Member Posts: 1
    I'm having the same problem. Any solutions? I also can not find on any parts websight how to buy a new switch.
  • hunterjohunterjo Member Posts: 1
    i have 2001 suburban the check 4wd light comes on sometimes and stays on until you turn car off. might not come for a week or two then does same thing again. there are no service codes in computer. any ideas.
  • fire305fire305 Member Posts: 2
    I had a problem where not only would my "SERVICE 4WD" indicator light come on, but it would actually shift itself into 4WD when I started it up. I replaced my dash 4WD switch w/ a new one. It cost about $55 w/ shipping. Since I have put it in, the "SERVICE 4WD" indicator light, has not come on. But, I have noticed as it starts to get warmer outside, I am still having the problem where I my Suburban will show the RED "N" light on my 4WD buttons. So I may have to actually get the Chevy dealership to look at it..... and then take out a loan to pay for it!!
  • rodonnellrodonnell Member Posts: 37
    This is a fairly common problem. Chevrolet has determined the Transfer Case Control Module sometimes does not get the "wake up call" it expects upon start up.

    There is a TSB issued, 02-04-21-006E. Available via subscription on All Data among other places. The TSB discusses removing the fuse as described in this forum. Failing that, the TCCM requires replacement. There is a reprogramming routine that must be performed on the new TCCM, have not done this myself but expect it is not all that difficult.
  • joker762joker762 Member Posts: 2
    I've got the same problem. What is the "TSB" and where might this fuse be located?

  • bryonsbryons Member Posts: 3
    One day while attempting to shift into 4wd high from 2wd, all lights went out on the 2wd-4wd-4wd low swith and the "Service 4wd" light came on. I had a '99 Tahoe that did this once and replcing the fuse worked. I did the same thing but it didn't help. I unhooked the battery to attempt to reset the 4wd and the "Service 4wd" light is no longer on but the problem still exists. It appears to be in 2wd now but the snow is coming! What's the deal?
  • chekchek Member Posts: 1
    To several of you on the forum, I noticed your concerns were over a year ago - so what happened? Did you have to replace the Transfer Case Control Module (TCCM)? I'm experiencing all of those systems you all have gone thru - the "check 4WD " message, no codes announcing anything's wrong, the off-on lite effect with the shift selection buttons etc. I went on Chevrolet Just, and got a definitive response to change the TCCM. Even got the repair manual guidance and instructions on how to do it - but havent done it yet. No where in the simple bolt out bolt in , unplug replug process does it describe a "reprogramming". Hope this info is of some value. Welcome any responses. My Tahoe is a 03 Tahoe LT.
  • bryonsbryons Member Posts: 3
    I felt pretty dumb when I realized there was an additional fuse under the hood of my 2001 Suburban (ATC) for the automatic transfer case. I had only checked the fuse inside the cab when the 4WD went out and it wasn't until I read another post that I realized there was another one. The ATC fuse was blown when I checked it. Even though the car wasn't on I heard the transfer case shift when I replaced the fuse. It has been fine since. Time to buy a couple more fuses! :shades:
  • ment2befarmsment2befarms Member Posts: 1
    Don't feel too bad Bryons. I too am going through the same thing on our 1997 Tahoe. Replaced Universals earlier this week. Then 4WD would not work. Got it to go into 4WD. Now it is tuck there. Checked all the connections and the dash fuse. Was ready to take it to the dealer until I found this forum. Tomorrow will be checking for the ATC fuse! Now if someone could tell me were it is located under the hood it would be appreciated! Thank you. :)
  • bryonsbryons Member Posts: 3
    The '99 and older are different but the one for my 2001 is located in a black plastic box under the hood above the left front wheel. I cross-referenced the "ATC" with the owners manual and found it for the automatic transfer case. It only made sense to check it, and, it had blown! Check your owners manual for exact location and what each fuse is for. Good luck! I hope you don't have to pay the dealer. $$$
  • niktnikt Member Posts: 24
    My 1999 Tahoe (odo reading 137,400 miles) won't go into 4 wheel drive. A couple of days ago the "Check 4WD" light came on for a while and then went off. I planned, but haven't done so yet, to get all the fluid levels checked this weekend. But now I see the red "Neutral" light is lit and I can't engage 4 wheel drive. I f there is a low fluid level sensor, can low transfer case or front diff lube cause this?
    Also, I want to check the ATC fuse per the above messages, but my owner's manual doesn't show where it is.
    Can any one please advise? Thanks,

  • azfiremanazfireman Member Posts: 4
    So I have to pose a question to all those out there in computer land who are smarter than me or happen to be mechanics or have had this issue before.

    I recently purchased a 1998 Tahoe with the right side of dash push button 4x4 with the auto 4x4 and the previous owner stated he was driving it in 4Hi and when he went to go into 2Hi it wouldn't shift and went into neutral.

    When I bought it the Transfer Case Shift Motor was removed I was able to shift it manually into 4Hi, 4Lo and neutral but couldn't seem to find 2Hi. I replaced the Shift Motor and checked the fuses and it still wouldn't shift. I did get the lights on the dash to blink for a while and then they seemed to go out completely.

    I took it to Chevy who put the motor back in (cuz I had to remove it to manually shift into 2wd) and stated it wasn't working because the Transfer Case Module under the dash was bad. $350 later plus labor they stated it tried to shift a few times and then burned out the Transfer Case Shift Motor $225 plus labor. After all this and not seeming to get it into 2wd they want me to replace the whole T-Case $750 used.

    Any advise before I replace the T-case or does this sound wrong to anybody else?
  • mmalkmmalk Member Posts: 2
    read some of the feed back.My problem is the indicator lt stays on in all wh, pressing the 2w 4w 4wlow dosnt shift.Replaced the modual in the dash still nothing , :mad: only 250 $not like azfireman.Will try the fuse removal senario.Any other ideas?
  • niktnikt Member Posts: 24
    Thanks for all the suggestions, but I can't find the automatic transfer case (ATC) fuse. I checked my owner's manual and looked at both the instrument panel fuseblock (on the left side) and the fuse panel under the hood on the left hand front fenderwell. Is there another fuse panel location not shown in my manual? I am going to try the battery disconnect method to see if re-booting the ECU and Trans Control Unit will help.

    I would appreciate hearing from anyone who knows where the ATC fuse is located on a 1999 Tahoe. Thanks for your help so far.

  • niktnikt Member Posts: 24
    To bryons,

    I realize your Tahoe is a 2001 and mine is a 1999, but where did you find the ATC fuse? I looked at my manual and opened the fusebox on the left front fenderwell, but didn't see the ATC fuse. The fusebox I opened has many fuses and relays in it. Is this the correct panel or is there another fusebox you're talking about, or does the ATC fuse have a different name or designation??

    Thanks, NIKT
  • niktnikt Member Posts: 24
    A big thanks to all who made suggestions. My 1999 Tahoe now has a correctly functioning 4WD system. If you recall, NIKT (that’s me) said that the unit was stuck in 2HI and would not engage any other mode. There were various suggestions, but here’s what worked for me:

    1.- Find ATC fuse. This took longer than everything else because I kept looking for an “ATC” fuse. At least on my ’99 Tahoe, there’s no fuse so marked. My manual did list a fuse in the small fuse panel on the left side of the instrument panel, but not in the panel over the left front wheel. It’s a 20Amp fuse in the No. 2 position, and is identified as “Transfer Case.” It was blown.

    2. – I pulled the T-case fuse (#2) and the Accessory Light fuse (#3) and left the car sit for about 5 minutes with the ignition switch off.

    3 – I replaced the 20 Amp fuse with a 25 Amp fuse, because some people suggested that cold weather can result in a higher current draw in the 2WD-4WD shift motor. I put back the 10 Amp Accessory Light fuse which was OK.

    4. – As some suggested, I then switched the ignition On and Off 5 times to clear any trouble codes stored in the Trans Control Module.

    5. – I fired up the engine and watched as the red “Neutral” light on the control button panel blinked off. My Tahoe had been stuck in 2HI, but then the 4HI button lit showing that mode was now engaged. I pushed the 2HI button and the transfer case shifted OK. Out on the street I engaged all the Transfer Case modes and everything seemed to work OK.

    Again, a big thanks to you all, and I hope what I did works for you too.

  • kiawahkiawah Member Posts: 3,666
    I'd put a 20Amp fuse back in. If you really do have some sort of problem (which will trip now the 25Amp fuse), you may burn some wiring (or a wiring block or connector) which would be very costly to repair.

    You can also keep another spare if it does blow later. If it does, you'll know exactly what are where to replace it.
  • mmalkmmalk Member Posts: 2
    checked the 20amp atc fuse that was to easy.subscibe to all data not all you want to know,. to seek more diagnostics.The selector seems to have power and replaced the modual.Has anybody gone further and replaced the tccm thier on ebay 165.00 pluged a scaner in ,no codes?
  • niktnikt Member Posts: 24
    To kiawah,

    Thanks for your thoughts. You make good sense and I will change the fuse back to a 20 Amp unit this morning and keep some spares handy, Also, I will operate the 4WD drive selection every other day or so to keep the shafts or other components moving freely.

    Also, is there another recommended lube oil for the transfer case? Some forums talk about a "blue" fluid for better lubricity, or is that to improve the Auto 4WD?

    You know, I have never used the Automatic 4WD feature. I bought my Tahoe used (50,000 miles) about 9 years ago. I tried using the Auto 4WD in the snow, but I didn't like what I thought was a harsh engagement and avoided ever using it. When accelerating on snow or wet pavement, I engage 4HI to get up to speed and then engage 2HI. In winter here in suburban Chicago, when we get blowing and drifting snow, I engage 4HI and it seems to get me through just fine. I then shift back to 2HI when I'm back on dry ground. I'm coming up on 140,000 miles and I like my Tahoe just fine. The only repairs of consequence (how do you spell Co$t?) have been replacement of one fuel injector and about 2 years later, the in-tank fuel pump.

  • markseilermarkseiler Member Posts: 2
    I have a 98 suburban 1500 4x4 LT 5.7 L with 165,000 miles

    I'm having some 4 x4 problems.

    The push buttons will engage 4 HI, but when it kicks in, the front wheels feel like they will pull to one side then the other and has an audible mechanical growl.

    I've never had a problem with the 4 wd system on this truck. I don't know where to start with diagnosis.

    The lights on the 4wd buttons all function, and the 4x4 system engages when each range is pushed , and dis-engages when 2 hi is pushed. It just pulls and growls when engaged.

    The symptom seems to be worse when using the auto 4 wd feature.

    Where should I start?

    I've had this rig since new.
  • niktnikt Member Posts: 24
    To Markseiler,

    I can't speak with the authority of a mechanic, but only from my perspective as a Tahoe owner. You may already know this, but don't engage 4WD on dry ground.
    If I correctly understand the way the 4WD system functions, engaging the front axle also causes the front axle to become a locked axle. That's necessary to prevent all the drive torque going to one wheel on very slippery ground, leaving you with very little or no traction. This means (to me) that one should avoid sharp turns of the front wheels while in 4WD unless you are on very slippery (snowy, icy) ground. I recall once forgetting to disengage 4WD and I could feel a terrific binding when I made sharp turns on dry ground.

    Did you read my previous entry? I bought my Tahoe used, and didn't like the way Auto 4WD engaged and never used again. Maybe a Tahoe technician could advise on lube oil specs for the transfer case. I hope this helps.

  • omegacanuckomegacanuck Member Posts: 1
    I have the same problem on a 2003 Chev Blazer, with nearly identical symptoms.

    If you believe the push button 4WD selector, all is fine. It switches in and out of 2 or 4WD no problem. However, based on recent driving I don't think it's actually engaged. If I actually get some decent slippage (ie, icy accelerating), it will grind from the front end like crazy. Sounds similar to grinding gears on a manual transmission (it's an auto, for reference). Only happens on slippage in 4WD.

    Took it into the dealer, they've replaced a seal which they say went bad and let oil into my vacuum lines which then took out a servo and actuator. Still grinds, so they're thinking it's actually taken chunks off the gear and sleeve for the 4WD. $800 so far into it, gonna be about $800 more for the gear and sleeve. :cry: Does this sound right for symptoms/diagnosis? I'm not much of a mechanic and REALLY get lost on tranny/transfer case type stuff.
  • niktnikt Member Posts: 24
    Sorry, I can't help on this one. I have to defer to a real mechanic on this problem.

  • markseilermarkseiler Member Posts: 2
    I took it to a shop, they said bad transfer case, they can put in a new one for $2,000

    i found a use one at the junk yard for $300. my friend and I are going to put it in and see what we get. They are supposed to be heavy so a little bit tricky to do in the driveway. I'll let you know how it turns out.
  • niktnikt Member Posts: 24
    After replacing the Transfer Case fuse (See my message #25), my 4WD worked OK for a while, but yesterday the fuse blew again and I now believe I have to replace the shifter motor. The local Chev dealer parts manager says the required motor is GM P/N 12386247 for $497.00! I did some digging and found a Dorman (new, not rebuilt) shift motor, Dorman P/N 600-902 that is supposed to be an exact replacement, and which costs $136.99 at RockAuto.

    Am I on the right track here? If not, any other suggestions?

    Has anyone out there made this repair? Is Dorman a reliable product?

  • grenneamgrenneam Member Posts: 4
    Hi Nikt,
    Looks like I have a similar problem with my wife's 1997 Tahoe as you are having. She shifted to 4WD the other day and now the thing is stuck in 4wd. Thanks to you I went right to the proper fuse and checked it - it was good. But I have a couple of questions about your entry #25, if you'd be so kind as to answer them. First; Why did you remove the Accessory Light fuse (#3) as well? Was that part of the reset procedure? Second has to do with switching the ignition On and Off 5 times to clear the codes. Can you tell me where you got that information. I'm asking becasue I couldn't find it on the web, but I may not have structured the search properly? Anyway either it's truly stuck in 4wd or I did something wrong because Nothing I did helped. :surprise:
  • niktnikt Member Posts: 24
    Hi grenneam,

    I pulled the the ATC and Accessory Light fuses because it was suggested by a Chev/GM mechanic in another forum. To understand what these fuses protected, and before doing any of the things I described, I tried to find schematics for the transmission control system at our local library without success, so I can't tell you what effect pulling the fuse had. That same mechanic suggested turning the ignition on and off 5 times.

    I thought I saved the the web address of that forum, but I couldn't find it in the my "Favorites" list. If I find it, I will let you know. I do recall it was an"Ask the Expert" style forum, and answers were free if were willing to wait a day or two for an answer. However, by paying a small premium you could get a quick return with an answer.

    Do you have any thoughts about, or know of anyone who used a Dorman shifter motor?


  • grenneamgrenneam Member Posts: 4
    For Nikt,
    Thanks for your reply. I forgot to pull the #3 fuse - I'll try it again with that out. I'm just getting into this stuff with this vehicle and am looking at replacing the TC motor as well. I really don't know anything about the Dorman Motor - just that it appears more expensive than the Cardone that I'm looking at.
    I feel like I've entered Automotive repair hell. I've got 2 vehicles that won't pass inspection, The Tahoe and my wife's 2001 Sienna. We made an attempt with the Tahoe and found out that not only was it not simple (cheap) to fix the 4WD problem but the MIL indicator was burnt out and it also needs a Cat converter and possibly something else. The Sienna is an even bigger nigthmare in that it too has Cat ConV problems and a bad KnockSensor. The Knock Sensor is about $180 and is located underneath the intake manifold so it'll be at least that much to replace it. The Fun part is that the Cat Conv for the Sienna looks like an Unobtainable part until at least Feb 2010 and cost somewhere between 350 and 1400 dollars depending on where I shop. It's also tucked away in such a manner to prohibit anyone with a blow torch from working their magic. The only saving element is that my State has a kickout clause on inspections that allows a Waiver if you spend > $150 on a vehicle trying to fix it. So that's a temporary solution. This has all happened over the last couple of days, I feel a little shell shocked and am just trying to orient my self with what is going on and who/what to try and fix first.. LOL :sick:
  • grenneamgrenneam Member Posts: 4
    OH yeah - I forgot this. In my web searches I found mention that replacing the TC motor might necessitate re-programming the TCM (Transmission Control Module)!! Have you seen anything like that? If you have, do you have any idea as to how that's done, or whether it a big deal or not ? :confuse:
  • droptinedroptine Member Posts: 1
    I have a 2003 Chevy Suburban 1/2ton. I had it in 4 wheel drive, snowy, slushy, wet and rainy. Driving about 50 the front end made a bunch of clanking noise and grinding. There was nowhere to pull off. I switched it into 2 wheel and was able to pull into a parking lot about 2.5 miles. I put it in park, then back into drive, it clanked once really loudly and then made no more noises until I tied to put it back into 4 wheel drive. Can you help?
  • niktnikt Member Posts: 24
    Thanks to all of you for your comments. I am just regular Tahoe owner, not a crackerjack mechanic, so I can't answer the questions you folks have. What little I know I learned from reading the Chilton and other shop manuals at our local public library and
    surfing the net to find other Chevy and Tahoe forums.

    I hope there is a guy with experience in these matters to advise us on repair and/or needed reprogramming procedures. I am digging into this as best I can because our local Chevy dealer wants $800 to $900 to replace the shift motor which is out of the question for guy not working a steady job (me). I just want to be sure I'm doing all the right things before I buy a shifter motor and try to install it.

    So once again, if any of you folks out there have replaced the shifter motor (sometimes called the encoder motor ( its GM part number is 12386247) please tell us all about and any problems you encountered.


  • niktnikt Member Posts: 24
    A note of caution for all to consider-----I mistakenly thought my Tahoe needed an encoder (2WD-4WD shifter) motor, of GM p/n 12386247 or Dorman 600-902. I did more checking (I should have done it first) and looked at the RPO codes on the ID sticker on the glove box door. Turns out that the transfer case RPO is not NP1, but actually NP8. The correct encoder (shift) motor is GM p/n 12474401 that is serviced by Dorman 600-901. The plugs and wiring are different and the units are not interchangeable.

    I'm sure a lot of you already know this stuff, but I confess to being a beginner. Years ago, when I scrounged for boneyard parts, RPOs and such weren't a factor--you just found what fit the car you were fixing. Of course my new questions are: Has anyone had experience installing this shifter motor? Any trick stuff to know about? Does any reprogramming have to be done? Is there a cheaper source for this motor?

    Many thanks to you all and Merry Christmas,

  • eds98burbeds98burb Member Posts: 1
    Ok I have been watching this thread and here is my problem. After recent snow I put the truck in 4 hi now it won't come out into 2wd. the dash switch clicks 2wd blinks then it goes back to 4hi. If you push 4 auto it will change into it but not 2wd. check 4x4 is on but I scanned it and it shows no codes. I pulled the fuses 2 and 3 waited 30 minutes reinstalled but that didn't do it. before i start throwing parts at it where do I start the switch ? My thinking is the transfer case motor 1st or switch 2nd because when the switch clicks i hear no noise at the transfer case. Any Ideas ?
  • grenneamgrenneam Member Posts: 4
    I have a very similar problem with my 97 Tahoe and I've got it in the Shop right now. The guy is supposed to replace a Part on Monday. I'll Let you know how it turns out. The vehicle is stuck in 4 whl Hi and won't go to either 2 whl Hi or 4 Whl LO. I don't have an auto button that I know of. It my wife's truck for pulling a horse trailer so I don't get involved with it much. :blush:
  • niktnikt Member Posts: 24
    My take on my problems as well as all of yours is that we all need to do more research and need some words of advice from a knowledgeable GM transmission tech.

    Does anyone know of a good manual, say a Chilton or Haynes that focuses on GM 4WDs and transfer cases? I looked in our public library, but came up short. I'm not comfortable changing fuses, etc., when I don't even have a clear understanding of how the transfer case operates and how the shifter motor interfaces with what I am sure are splined shifting collars.

    I suspect many of you are a lot more knowledgeable on how a transfer case functions than I am, and if you can help, please pitch in because I'm sure we could all learn something.

    Thanks and Merry Christmas,

  • kiawahkiawah Member Posts: 3,666
    You can order a set of factory service manuals for your vehicle. Check the back of the owners manual for the ordering details. They are a HUGE 3 volume set, which goes into intimate detail of everything. I always order a set for every vehicle I have bought. If it saves you one trip to the dealership repair department, it pays for itself.
  • niktnikt Member Posts: 24
    Hi kiawah,

    Thanks for your courteous and prompt response. I will follow up on your suggestion.

  • notawrenchguynotawrenchguy Member Posts: 8
    I have a Silverado 4WD. The electronic push button will go from blinking to a solid light when pushing either 4 wheel High or 4 wheel Low, but the front wheels don't engage.
    Anyone know whats going on?
  • niktnikt Member Posts: 24
    Re: notawrenchguy

    Take a look at previous messages. Check the transfer case fuses.

    If the fuse(s) are blown, there is a chance that the shifter motor is shot, and you may need a 4WD/2WD shifter motor, also known as an encoder motor. To correctly identify which one your Siverado uses, be sure to check your serial number/option data plate. Check your owner's manual for its location. Copy down the N-codes to determine which transfer case you have and the shifter motor you might need.

    With the correct n-code, a cooperative GM parts counterman should be able to give you the correct encoder motor P/N.

    Hope this helps.

  • notawrenchguynotawrenchguy Member Posts: 8
    I'm lookink for the (ATC) fuse and am a little confused! I have a 2004 Silverado (electronoic) 4WD. I'm looking for my various 4 WD related fuses in the owners manual and find one labled "TREC" (All-wheel Drive Module) , one marked "4WD" (Four Wheel Drive System, Auxiliary Battery), one marked "B/U LP" (Back-up lamps, Automatic Transmission Shift Lock Control System) , but I'm not finding one marked "ATC" (Automatic transfer Case)
    These include fuse panels in the cab and under the hood.
    Any thoughts or direction??

    I looked at my owners manual
  • notawrenchguynotawrenchguy Member Posts: 8
    Thanks for your reply and suggestions
    I'll check the fuses first and pray, although I've reveiewed some previous messages and just sent out another "question" because I can't find a fuse labeled (ATC) Automatic Transfer Case.
  • 85350x85350x Member Posts: 2
    i have a 96 suburban. i've read through all the posts and didnt see anything on older suburbans. mine is in 2hi and if i shift to 4hi or 4 lo the indicator lights flash. i can hear the transfer case engage but i dont think the front differential is engaging. I had a 94 suburban and i replaced the differential acctuator and that fixed the problem on it but it had a lever on the floor to engage 4wd. i checked fuses and didnt see one for the t-case in the fuse block under the hood. will look again.
  • niktnikt Member Posts: 24
    To all,

    Just so you all know, my experiences with 4WD have been limited to my 1999 Tahoe and its particular transmission, 4WD control configuration, and fusing.

    I can't speak with any authority on any other year or model GM product (heck, I can't speak with any authority on my own Tahoe).

    My suggestion would be to check all fuses that seem to relate to the 4WD controls and replace any blown fuses. Then try the system. My Tahoe did have a blown fuse which I replaced, and I did restore 4WD operation. After a week, the fuse again blew. I have ordered a new shift motor from Rock Auto to make a hopefully permanent repair.

    I caution you all to check your option data plate to confirm the transmission option codes to get the correct parts. In my area, a helpful Chevy dealer parts guy gave me the GM p/n for the shift motor for that code.

    I can only say that fuses blow because of excess current and that usually means the encoder (shift) motor is possibly faulty and must be replaced

  • notawrenchguynotawrenchguy Member Posts: 8
    Thnaks for the info.....I've checked all the fuses I could find ( as I mentioned in my message # 49) but didn't find out that were blown????
    Today I'll look around under the truck for loose conections, etc.
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