Front Axle Will Not Disengage

Circuit Description
The front axle control circuit consists of an electric motor actuator which engages and disengages the front axle. The front axle actuator's motor consists of a Permanent Magnetic (PM) motor, a worm gear controlled plunger, a front axle switch and an electronic control circuit all within the actuator assembly. The front axle actuator has four circuits connected to it. CKT 241 supplies ignition voltage to the actuator. CKT 2150 provides the ground. CKT 1695 is the front axle switch, and CKT 1570 is the front axle control.
Whenever a shift to AUTO, 4WD, 4HI, or 4LO is requested, the automatic transfer case control module engages the front axle by grounding the front axle control CKT 1570 through a current limiting driver.

Test Description
The number(s) refer to the step number(s) on the diagnostic table.
2. This step determines if the scan tool has electronic control of the front drive axle clutch solenoid.
3. This step determines if the failure involves the front drive axle clutch solenoid or the front axle switch.
4. This step tests for a shorted condition at the front drive axle clutch solenoid.
5. This step determines if the front axle engagement is do to a short to ground condition on the ground side of the front drive axle clutch solenoid.
6. This step determines whether the shorted condition is in CKT 1570 or inside the transfer case shift control module.
7. This step tests the controller's ability to sense an open condition at the front axle switch.
8. This step tests for a short to power condition in CKT 1695.
10. This step tests for a leaking vacuum valve at the front drive axle clutch solenoid.