Front Axle Will Not Disengage

Front Axle Will Not Disengage





Test 1-5





Test 6-17

Circuit Description
The front axle control circuit consists of an electric motor actuator, which engages and disengages the front axle. The front axle actuator 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:
^ Ignition 3 voltage circuit
^ Ground circuit
^ Axle actuator control circuit
^ Axle switch signal circuit Whenever a shift to 4HI, or 4LO is requested, the transfer case shift control module engages the front axle by grounding the axle actuator control circuit through a current limiting driver.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step tests the electrical function of the front axle actuator. Helps determine between mechanical and electrical malfunctions.
3. This step tests for proper power and ground at the front axle actuator.
4. This step tests the operation of the axle actuator control circuit.
5. This step tests the electrical function of the axle actuator control circuit.
6. This step tests for proper ignition 3 voltage to the front axle actuator.
7. This step tests for open fuse in the ignition 3 voltage circuit.
8. This step tests the axle actuator control circuit for an open or high resistance.
9. This step tests the axle switch signal circuit for an open or high resistance.
10. This step helps determine if the front axle actuator has a mechanical malfunction.
11. This step tests the axle switch signal circuit for a short to voltage.
12. Inspect the front axle for a mechanical malfunction.