Hello my name is Steve W, the 4x4 shift motor on these vehicles is the most common concern, what you can try is have someone push the buttons while you tap on the shift motor with a hammer and see if the 4x4 starts to work. The contacts inside the motor usually build up some corrosion and they intermittently won't work at all.
Any more questions just ask, Thanks Steve W
Thank you, I followed your advice and heard nothing. I also unplugged the harness where it ended at the shift motor. There is a yellow wire with a white stripe that has a low voltage current with the 4X4 button pushed or not. No other wires will light up a test light even when either the 4X4 button or the low range button is pressed.
Here is a pinpoint test for dead 4x4 system, check all fuses first, then check the 4x4 module and see if it flashes 4 times, then follow along with the test and see if you reach a conclusion, any more questions just ask, Thanks Steve W
Pinpoint test click here
O.K. I checked the fuses. All were good. I checked the 4X4 module as per the instructions. It did flash four times. I checked my grounds (except one). They are tight and clean. The one I could not find is where the black wire goes to off of the shift module. I checked and cleaned the battery posts in the event that it ran clear back to there.
The one thing that I did find that didn't seem right was that the W/LB 465 wire from the module to the shift switch and 762 Y/ W from the module to the motor position sensor only are carrying about 5 volts. Does this point to the module?
Oh, the wires feeding the module from the battery and the ignition switch both are carrying a good 12 volt charge.
I believe the 5 volts you seeing is normal, its what they call a reference voltage, since you have power and grounds are good, the most likely cause is the 4x4 shift motor, the module needs to see the position of the 4x4 motor by looking and the position sensor all built into the 4x4 motor, if it doesn't see the position, it will not initiate a shift.
Should be looking at the position sensor, spell check.
I'm sorry, I kept bumping the enter button when I didn't intend to. I really appreciate you staying with me as I didn't have time to immediately get to the next steps. You did a great job of diagnosis! Thanks again.
Steve, the 4x4 shift motor was the problem.