The front axle control circuit consists of an electric motor actuator which engages and disengages the front axle. The front axle actuator consists of the following components within the actuator assembly:
• | A permanent magnetic motor |
• | A worm gear controlled plunger |
• | A front axle switch |
• | An electronic control circuit |
The front axle actuator consists of the following circuits:
• | An ignition 3 voltage circuit |
• | A ground circuit |
• | An axle actuator control circuit |
• | An axle switch signal circuit |
Whenever a shift to 4WD is selected, the transfer case switch engages the front axle by grounding the axle actuator control circuit.
The numbers below refer to the step numbers on the diagnostic table.
Tests for proper ignition 3 voltage to the front axle actuator.
Tests for proper ground at the front axle actuator.
Tests the axle actuator control circuit and transfer case switch for a short to ground.
Tests the axle actuator control circuit for a short to ground.
Step | Action | Values | Yes | No |
---|---|---|---|---|
Schematic Reference: Transfer Case Control Schematics | ||||
1 | Did you perform a Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
Does the voltage measure within the specified value? | 9-14 V | Go to Step 3 | Go to Step 6 | |
Does the voltage measure within the specified value? | 9-14 V | Go to Step 4 | Go to Step 7 | |
Does the test lamp illuminate? | -- | Go to Step 5 | Go to Step 9 | |
Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 10 | |
6 | Repair the open in the ignition 3 voltage circuit. Refer to Circuit Testing and Wiring Repairs. Did you complete the repair? | -- | Go to Step 11 | -- |
7 | Repair the open in the ground circuit. Refer to Circuit Testing and Wiring Repairs. Did you complete the repair? | -- | Go to Step 11 | -- |
8 | Repair the short to ground in the axle actuator control circuit. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | -- | Go to Step 11 | -- |
9 | Replace the front axle actuator. Refer to Front Drive Axle Actuator Replacement. Did you complete the replacement? | -- | Go to Step 11 | -- |
10 | Replace the transfer case switch. Refer to Transfer Case Gear Indicator Switch Replacement . Does the scan tool display the status Front Axle Switch Locked? | -- | Go to Step 11 | -- |
11 | Operate the vehicle in order to determine if the symptom has been corrected. Is the symptom still present? | -- | Go to Step 2 | System OK |