The driver and front passenger power door lock switches are integral components of the driver door module (DDM) and passenger door module (PDM). The switches consist of 2 positions, lock and unlock, and are in the normally open state. When placed in either the lock or unlock positions, the switches provide a direct input to there respective door control module. When a power door lock switch is operated to the lock or unlock position, the associated door control module responds by sending a GMLAN serial data message indicating a change in the switch's position. This serial data message is received by the opposite door control module as well as the body control module (BCM). The DDM and PDM respond to the lock/unlock request by activating there associated power door lock motors to the appropriate direction to lock or unlock the front doors. The BCM is responsible for controlling the left and right rear passenger door lock motors. The BCM, upon receipt of a lock or unlock serial data signal, will control either the rear door lock or unlock relay. When the appropriate door lock relay is energized, the rear power door lock motors will lock or unlock the rear doors.

Schematic Reference

Door Lock/Indicator Schematics

Connector End View Reference

Vehicle Access Connector End Views

Description and Operation

Power Door Locks Description and Operation

Electrical Information Reference

Scan Tool Reference

1. Ignition OFF, disconnect the harness connector at the driver door latch assembly.
2. Ignition OFF, scan tool OFF, test for less than 10.0 ohms of resistance between the ground circuit terminal 8 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the scan tool door key cyl. unlock switch parameter is IDLE.

⇒	If not the specified value, test the signal circuit terminal 9 for a short to ground. If the circuit tests normal, replace the DDM.

4. Install a 3-A fused jumper wire between the signal circuit terminal 9 and the ground circuit terminal 8. Verify the scan tool door key cyl. unlock switch parameter is UNLOCK.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the DDM.

5. If the circuits test normal, test or replace the driver door latch assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.