Help '99 Tahoe 4wd won't disengage

[SunlitComet]

How about testing the selector module? interested?

---------- Post added at 11:20 PM ---------- Previous post was at 11:19 PM ----------

You will need a multimeter btw.

 

[TurboBu]

I'm game. I'm an HVAC tech, I used one of those electronic gizmos once.

 

[SunlitComet]

No kidding. Used to do hvac myself. Sometimes still help others. Especially on cars. Got the certs might as well use them. Now I work on aircraft.

I can either call out the procedure and wire to probe or if you PM an email address I can send you pdf files of various things like procedures, diagrams and what not. Need to mention on thing first. anytime picture like diagrams or some graphical item is converted to pdf the color is inverted. so for a diagram instead of a white page with black circuits and writing it will be a black page with white circuits and writing. That can take its toll on on inkjet if you have one.

At any rate let me know.

 

[TurboBu]

That would be great. [email protected] I have a lazerjet, fast but cartridges are$$$

 

[SunlitComet]

I hear ya. My cartridge cost $240 each. But good for 20,000 pages though The first one has been sent. You will want to be testing the two terminals H-C2 and A-C1 for the various resistance values when a button is depressed and not.

 

[macster2751]

i dont know if this will help but here is something

Problem solved, Here's the solution I purchased the truck from someone that never used the 4wd. The transfer case shift sector was very tight from no use. I installed a new transfercase Teflon(R)-coated shift detent plunger (poppet) GM Part #12474072 and fresh auto trac II fluid. Then put a cresent wrench on the shift sector coming out of the transfer case and worked it at least a 100 times until it felt like shifting my motorcycle trans nice easy clicks. It was so tight before it was causing the encoder motors to fail right away. I had the transfer case scanned at the dealer twice and it said bad encoder motor open circuit both times 2 new motors turned into junk. The parts store was good about taking the motors back. Now I think every fall I will remove the encoder motor work the shift sector with fresh auto trac fluid in the transfer case before winter.

Where is the shift detent plunger located???

Thanks Mac

 

[rabbiporkchop]

My 1999 2Dr Tahoe is stuck in 4wd. If I push the 2wd button I can hear what sounds like the front end disengaging the 4wd light goes off or flashes, then I hear the front engage again and the 4wd light comes on. I've tried in park, neutral, drive, reverse, and coasting forwards and backwards.

try putting it in reverse and driving backwards as you push the button. My wifes 99 did the same thing.

 

[SunlitComet]

if your vehicle defaults to 4wd hi even after you disengage it and get 2wd momentarily then it is very likely you shift motor encoder has failed.