Front Axle Will Not Disengage

Circuit Description
The front axle control circuit consists of a Front Drive Axle Clutch Solenoid which is electronically controlled by the transfer case shift control module. This solenoid opens and closes a vacuum control valve allowing vacuum to apply and release a clutch pack inside the front axle housing. The transfer case shift control module determines whether or not the clutch pack has been applied or released based on a signal from the front axle switch mounted on the front axle housing assembly. The front axle is normally locked or engaged during AUTO 4WD, 4WD Hi, and 4WD LO modes. The front axle is unlocked or disengaged only during 2 HI or neutral modes.









Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
2. Helps determine whether the transfer case shift control module has electronic control of the front axle actuator. Visual inspection of the front axle to determine if the front axle is mechanically engaged.
4. Helps determine if the front axle control circuit is shorted to ground.
5. Tests the front axle control circuit for a shorted to ground.
6. Helps determine whether the short to ground is due to faulty wiring or module.
7. Helps determine a faulty front axle switch.
8. Tests the front axle switch signal circuit for a short to voltage.
9. Helps determine whether the short to voltage is due to faulty wiring or module.
10. Helps determine a faulty front axle actuator.