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:

The front axle actuator consists of the following circuits:

Whenever a shift to 4WD is selected, the transfer case switch engages the front axle by grounding the axle actuator control circuit.

Schematic Reference

Transfer Case Control Schematics

Connector End View Reference

Transfer Case Control Connector End Views

Electrical Information Reference

1. Place the vehicle in 2WD install a scan tool and using engine data 2 look at the display for 4WD signal.
2. Verify that the scan tool indicates that the vehicle is in 2WD.

⇒	If the scan tool indicates that the vehicle is in 4WD go to circuit system testing.

1. Check the axle switch signal circuit for a short to voltage.

⇒	If everything checks normal then go to the next step.

2. Check the front axle actuator control circuit for a short to ground with the front axle actuator disconnected and the mode selection switch disconnected.

⇒	If everything checks normal reconnect the mode selection switch and retest. If the circuit shows a short to ground then replace the switch. If the circuit indicates no short to ground then refer to front axle actuator and axle testing.

Remove the actuator and attempt shift from 2WD to 4WD, if the actuator moves check the front axle actuator plunger and fork assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.