I had very similar issue, but I have a 98 Jimmy. Since Garv only has 1 post I am assuming he never posted how it worked out for him. It would blow once in a while.. often while I was backing out of my driveway.

The issue has turned into something different. I originally pulled the connector from the encoder (under the truck). and have since put it back. This was at the end of last winter.. so I have never tried to engage 4x4 since. Now, the other day I test out since my street is slick.. the 2WD light stays on, but pushing 4WD HI or 4WD Lo does nothing. Not even a flashing light on either button.

the good news is that the fuse (#15) has not blown since last winter/spring.

I did the diagnostic test as described elsewhere on this forum (THANKS!) and got code 2. I have tried pulling the ATC fuse under the hood for half and hour.. and the fuse 15 (4x4) in the inside fuse box. still does not work. May I have better luck if I disconnect the battery? I could figure no other sensible fuses to pull to reset the TCCM.

I may go back under the car and disconnect the encoder cable and inspect and reconnect. Is it possible that I could simply replace the motor/encoder and be done with it? I noticed that sometimes they do not come out easily according to another post I read again on this forum (THANKS) If it does not come out easily am I hosed until I get it out or can I give up and re-tighten it back up until I can have a car mechanic friend look at it? I also don't want to waste money on getting a new motor/encoder and have that not be it.

Thanks for any words of encouragement or wisdom in this matter.

 

*Moved out of THIS THREAD due to thread age*

Your problem likely is caused by a faulty encoder on the encoder motor. They are one assembly. Replacement will likely cure your problem. If you would like to do more testing, you can have a look at error401's post in the Tech Article (DIY) section where he gets pretty into the inner workings of the NV233 control system.

 

I assume what I need is to replace the entire transfer case motor then?
I am looking on Rock Auto, and I see about 6 different TCMs under the 1998 GMC Jimmy. Is there any easy way of knowing exactly which one I need?

There are 3 manufacturers.. Cardone, Retech, and Doorman. I'd probably go with the Cardone. But I need to know if its a 2 or 7 pin connector. Any way of knowing without crawling under the car and removing the connector?

 

The easiest and most sure way of knowing is to take a look at what you have already. If you have the 3-button switch in the dash, you have the NV233 transfer case. This should be a 7 pin plug. I do not know what application would have only a two wire plug...

 

The easiest and most sure way of knowing is to take a look at what you have already. If you have the 3-button switch in the dash, you have the NV233 transfer case. This should be a 7 pin plug. I do not know what application would have only a two wire plug...

 

Thanks. Has the 7 pin layout. I opted for the new (as opposed to refurb).. and is ordered. I am now praying for fast shipping.. to beat any snow that may come in. The Jimmy blows in the snow in 2WD.

 

Alright.. I have the new TCM. I have the 3 bolts off the one on the transfer case, but no room to get it fully out without removing the front drive shaft. I have the driveshaft disconnected at the u-joint, and with some hard persuasion, got the shaft away from the u-joint. Now I'm trying to get the drive shaft from the transfer case. It does not want to budge. I have tried a bit with a pry bar. are there any tricks to getting this sucker off there? or just keep beating at it with a pry bar?

My garage is 30 degrees today and I am not enjoying my time under the car...although for me getting the drive shaft off the ujoint was a happy point of my day. (as I have never dug this far under my car before)

Thanks.

Edit.. I've spent almost 2 hours trying to get the new TCM onto the transfer case. does not want to line up. I have moved the transfer case with a crescent wrench. Seems to have 3 detents. 2 of them I cannot turn the front axle.. and the 3rd I can.. so I am assuming thats 2WD since the FWD axls seems to spin freely. That 2WD position ALMOST lines up with the TCM.. but not quite. There just seems absolutely no way to get them to line up. I am begging now for any little tips to get this to line up.

 

Where did you get with this? Did you get it aligned?

 

nope. I needed the car for work the next day, so I put it back together with the old one.. and its been fine over the past week. I'll try the new one some other weekend.. when its warmer out. I guess my only shot is to hook it up to the connector, actuate it and see if it lands in a correct location then install it.