1999 blazer/jimmy 4wd problem, please look

[privatepilot03]

I came in from the garage for 2 reasons..

1. Create this post seeking help.

2. Prevent me from lighting my Jimmy on fire and watching it burn to the ground..

First off, my truck is a 1999 Jimmy with pushbutton 4wd. It's the 4 button switch (auto 4wd, 2hi, 4hi and 4lo) if it matters. Anyway, I can hear the TCCM relays clicking when I turn the key on, but I can't get it to change from 2hi to anything else.

So based on some reading here and at other forums, I determine that the encoder motor is bad. I removed it and found it to be severely corroded to the point that the aluminum housing had cracked. So I bought a new encoder motor. Last night I installed it and magically, the 4hi light lit up when I pushed the button. I also heard the encoder motor moving, so I figured I was good to go. I put the driveshaft back in, pulled out of the garage into the alley. I put the truck in neutral and hit 4lo. I heard a terrible, mechanical clunk after a couple seconds, then the 2hi light lit up and stayed there. I tried it 2 more times (with the truck stopped as well as with the truck just barely rolling in neutral) without avail. The last time however, the transfer case got stuck between 2 settings and I could no longer moved the truck. I removed the driveshaft and encoder motor so I could manually select a gear (all this in pitch darkness while laying in the slush and snow in my alley) and get the truck back in the garage.

Today after work, I reset everything, reinstalled the encoder motor and like last night, I was able to select 2hi or 4hi. Cool.. So I drove around in 4hi for a little bit, came back home and tried 4lo again. It tried to engage 4lo but failed and put it back in 2hi. This time, it errored out and displayed the service 4wd light.


That's where I'm now stuck. I've unplugged the TCCM, disconnected the battery, pulled the 4wd fuse and every time I turn the key on, the TCCM relays click a few times and it goes "service 4wd"..

So I now ask.. WTF? I'm content to have just 4hi for the time being, but I can't get the damn thing to even do that now. What should I try next?

Frustrated in Wisconsin with a snow storm coming this weekend......

Chad

[MT-2500]

You need to get it on a transfer case capable scanner and check for codes and post back any code no.
A good transfer /transmission capable scanner also has some shifting test built in it to also aid in finding the problem.
Without the scanner is is a crap shoot trying to find the problem.
MT