Service 4wd when using 4wd

[rparikian]

Hello everyone. I wanted to ask the community for advice on my 2002 Tahoe Z71. I am having some issues with the 4wd. To sum it up when I click the button for 4wd low the light blinks a few times and then switches back to 2wd. Same for 4wd high. I can switch to auto, but it disengages on sharp turns or after a few miles of driving. That's when:secret:I get the service 4wd light. I also get it when I try to switch to 4wd and it seems to not work.

I have read numerous posts on numerous boards. I changed the 4wd switch cluster. I had the encoder motor replaced. Nothing seems to fix it. I have not tried having the controller reprogrammed yet. My last choice is to have the transfer case serviced to see if there are any issues.

Has anyone seen this problem? Can you recommend a course of action?

TIA

 

[bluetahoe2211]

First start with the fuse under the hood. Bottom right ATC or TREC 30 amp. Then since you already replaced the switches how bout checking the harness to the encoder motor. I hate to break it to you but from my knowledge the motors aren't what tend to go out, but it the encoder motor sensor inside behind the gear on the left. Also known as transfer case ring $60. The other culprit is the TCCM (transfer case control module) about $200

 

[rparikian]

Is the encoder sensor part of the encoder motor? If they tried replacing the motor, wouldn't they have replaced that as well? Also, where would i find the wiring harness for the encoder motor?

 

[bluetahoe2211]

yeah true. The sensor is in the motor behind the left gear so if you bought the whole motor then your ok there. Their are two harnesses if I'm not mistaken. One to the motor and one to the sensor. You will find them above the encoder motor assembly by the transfer case. I hear the plug connectors are a pain to disconnect. Havn't ever done one. I think there is a safety clip type thing on top you have to first pull up, then the plug has a regular clip on the side. Maybe someone who knows for sure can reply....

 

[Grebbler]

What about the front diff encoder?