2002 Chevy trailblazer

I just bought a 2002 Chevy and the electronic 4 wheel won't engage when u push the button. Does anyone have a wiring diagram so I can trouble shoot my problem?

wow this one looks interesting I think I would start with establishing 5 volts to switch from transfer case module any moderators or experienced technicians have any input on where to start

Congrats on the new (to you) Chevy!

Codes and scan data are definitely the place to start with these systems. If you don't have a scanner, then at least a code read from the Transfer Case Shift Control Module would be helpful.

Encoder motor potentiometer issues are commom, but not common enough that I'd suggest throwing one at it. :lol: If you can't get codes or data, then we can suggest some voltage tests at the shift control switch and the encoder motor.

Thanks for the replies anyone have a description of how the system works

Fordman wrote: Thanks for the replies anyone have a description of how the system works

The TCSCM provides 5V to the range switch, and the switch pulls that down to varying voltages depending on the switch position. Once the requested range is achieved, the TCSCM lights the corresponding LED on the switch. i.e. you asked for 4HI, the TCSCM moves the transfer case around, then lights the 4HI LED when it gets there.

When a range is requested, the TCSCM spins the transfer case motor in either direction while watching the encoder voltage (the encoder corresponds to transfer case position). Once the encoder voltage reaches the desired point, the motor is stopped.