Not shifting from two wheel drive to four wheel drive

Hello,

One of two things happens on these trucks, first is the switch goes out and the next is the encoder (actuator) goes out both cause the light to come on. I would try the switch first.

Here is a wiring diagram of the system and a guide to help you confirm the failure:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Here is a guide to help you check the wiring:

https://www.2carpros.com/articles/how-to-check-wiring

You should check the fuses as well.

Check out the diagrams (below).

Please let us know what you find.

Cheers, Ken