96 k1500 4x4 question

My 96 k1500 has push button 4 wheel. when you push either 4 hi or 4 low it shifts into 4 wheel but then shifts back out only a second later. you can hear the relays clicking in and out under the dash, you can hear the transfer case engage aswell. I havent been able to check for voltge at the front actuator because it shifts in and back out to quick for me to check by myself, although I only changed it a year ago.
Any ideas would be much appreciated.

My 96 k1500 has push button 4 wheel. when you push either 4 hi or 4 low it shifts into 4 wheel but then shifts back out only a second later. you can hear the relays clicking in and out under the dash, you can hear the transfer case engage aswell. I havent been able to check for voltge at the front actuator because it shifts in and back out to quick for me to check by myself, although I only changed it a year ago.
Any ideas would be much appreciated.
What transfer case?
Auto matic 4W or 3 button reg shift transfer case?
If old 233/243 - 3 button you can ground pin 13 on diagnostic connector and read codes on shift button lights.
Post back codes.

Thanks for the reply.
It is the 3 button 243 transfer case. I tried grounding out pin 13, as soon as it is grounded the light on the 2 hi button goes out and does not flash any codes. Just to be sure pin 13 is 3rd from the right on the bottom, correct?

With pin 13 grounded key off turn key on and it should flash codes of 1-4.

If no codes next step would be to get a repair flow chart on it and go threw the repair flow chart.

Good luck

Okay so I have checked for codes a few times now and dont get any. After checking for damaged or loose wires I could not find anything out of the ordinary. after repeatedly pressing 4 hi it suddenly locked in and i can switch from 4 hi to 4 lo BUT NOW IT WONT GO BACK INTO 2 HI. when you press 2 hi the light blinks twice , you can hear the shift motor moving but it goes back to 4 hi. Maybe this narrows it down to a weak shift motor?

I had mine stick in 4x4 low one time leaving the lake. I didn't know what to do and didn't want to drive it very far with it in Low.

I backed up while pushing 4x2 and it popped out of 4x4 low. I am not sure why it did it, but it has been fine ever since. Locks in and out normally now.

Well after further troubleshooting I found that the encoder motor did not have enough torque to fully shift the transfer case. I changed the motor only to find the new one did not either. When I had the encoder off i could shift the transfer case with a wrench but it took alot of force to do it so im thinking that their is something wrong inside the transfer case and that I need a rebuild. Crap!

Well after further troubleshooting I found that the encoder motor did not have enough torque to fully shift the transfer case. I changed the motor only to find the new one did not either. When I had the encoder off i could shift the transfer case with a wrench but it took alot of force to do it so im thinking that their is something wrong inside the transfer case and that I need a rebuild. Crap!

You may want to drain the t-case and refill with GM Auto-Trak ll P/N 12378508 fluid and see what happens. It's not cheap stuff but it could save you a rebuild if it works. When you drain it try to use a coffee or paint filter to catch any thing unusual that comes out.