Quote:
Originally Posted by Shadyvol
98 Jimmy 180k, Shift to 4-WH and can hear actuator shift. 4W-L works also. Yet the front hubs do not lock. Button lights show no problem. Checked all fuses. None blown that I could find. Can not hear any vacuum leak. ???
|
This could be more complicated than you think. I was through this last summer with my 2001 Jimmy. I would push 4WD and it would blink but not change into 4WD. If it's trying to change, you will hear it trying as you drive. At that point, it may not be vacuum related. Sometimes it would change to 4WD but eventually it stayed in 2WD over time. At that point, it could be vacuum related. Everybody above is right. You must check all vacuums incl. the actuator under the battery and measure voltages to the Transfer Case Control Module (TCCM) located against the wall under the glove compartment. You must remove the plastic Trim Panel.
What I found on my Jimmy after a very long diagostic process was that I had some water dripping on the wiring harness into the Transfer Case Control Module. It must of shorted it because a couple of pins were very corroded. Harness plug had to be rewired. It still didn't work. Finally I broke down with the replacement of the TCCM which is $500.