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

Electrical Information Reference

Scan Tool Reference

1. Ignition ON, observe the scan tool Driver Door Open Sw. parameter located in the Driver Door Switch Data Display Inputs menu while opening and closing the driver door. The reading should toggle between ACTIVE and INACTIVE.

⇒	If the reading does not change between the commanded states, refer to Door Open Switch Malfunction - Front.

2. Observe the scan tool front Passenger Door Open Sw. parameter located in the Passenger Door Switch Data Display Inputs menu while opening and closing the passenger door. The reading should toggle between ACTIVE and INACTIVE.

⇒	If the reading does not change between the commanded states, refer to Door Open Switch Malfunction - Front.

3. Observe the interior lights while opening and closing the left rear passenger door. The interior lights should illuminate as the left rear door is opened.

⇒	If the interior lights do not illuminate, refer to Door Open Switch Malfunction - Rear.

4. Observe the interior lights while opening and closing the right rear passenger door. The interior lights should illuminate as the right rear door is opened.

⇒	If the interior lights do not illuminate, refer to Door Open Switch Malfunction - Rear.

Power Door Lock Malfunction - Front

1. Ignition OFF, disconnect the harness connector at the inoperative front door latch assembly.
2. Ignition ON, verify that a test lamp does not illuminate between B+ and the door lock actuator lock control circuit.

⇒	If the test lamp illuminates, test the lock control circuit for a short to ground. If the circuit tests normal, replace the appropriate door control module.

3. Ignition ON, verify that a test lamp does not illuminate between B+ and the door lock actuator unlock control circuit.

⇒	If the test lamp illuminates, test the unlock control circuit for a short to ground. If the circuit tests normal, replace the appropriate door control module.

4. Ignition ON, verify that a test lamp does not illuminate between ground and the door lock actuator lock control circuit.

⇒	If the test lamp illuminates, test the lock control circuit for a short to voltage. If the circuit tests normal, replace the appropriate door control module.

5. Ignition ON, verify that a test lamp does not illuminate between ground and the door lock actuator unlock control circuit.

⇒	If the test lamp illuminates, test the unlock control circuit for a short to voltage. If the circuit tests normal, replace the appropriate door control module.

6. Ignition OFF, connect a test lamp between the lock control circuit terminal and unlock control circuit terminal at the door latch harness connector.
7. Ignition ON, perform the DOOR LOCK/UNLOCK test with a scan tool. The test lamp should turn ON and OFF when performing the DOOR LOCK/UNLOCK test.

⇒	If the test lamp remains OFF during either of the commands, test for an open/high resistance on either control circuit. If the circuits test normal, replace the appropriate door control module.

8. If the circuits test normal, test or replace the inoperative door latch assembly.

Power Door Lock Malfunction - Rear

1. Ignition OFF, disconnect the lock relay.
2. Test for less than 1.0 ohm of resistance between the ground circuit terminal 2 and ground.

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

3. Test for less than 1.0 ohm of resistance between the ground circuit terminal 4 and ground.

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

4. Connect a test lamp between the B+ circuit terminal 1 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 5 for a short to ground. If the circuit tests normal, test or replace the lock relay.

5. Connect a test lamp between the control circuit terminal 3 and the ground circuit terminal 4.
6. Command the rear door locks to LOCK and UNLOCK with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.

⇒	If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

7. Ignition OFF, disconnect the unlock relay.
8. Test for less than 1.0 ohm of resistance between the ground circuit terminal 7 and ground.

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

9. Verify that a test lamp illuminates between the B+ circuit terminal 6 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 10 for a short to ground. If the circuit tests normal, test or replace the unlock relay.

10. Verify that a test lamp illuminates between the B+ circuit terminal 8 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

11. Connect a test lamp between the B+ circuit terminal 8 and the control circuit terminal 9.
12. Command the rear door locks to LOCK and UNLOCK with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.

⇒	If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

13. Connect the lock relay.
14. Connect the unlock relay.
15. Disconnect the harness connector at the inoperative rear door latch assembly.
16. Ignition OFF, scan tool OFF, test for less than 5.0 ohms of resistance between the lock control circuit terminal B and ground.

⇒	If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the lock relay.

17. Test for less than 5.0 ohms of resistance between the unlock control circuit terminal A and ground.

⇒	If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the unlock relay.

18. Connect a test lamp between the lock control circuit terminal B and ground.
19. Command the rear door locks to LOCK with a scan tool. The test lamp should turn ON when commanded.

⇒	If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the lock relay.

20. Connect a test lamp between the unlock control circuit terminal A and ground.
21. Command the rear door locks to UNLOCK with a scan tool. The test lamp should turn ON when commanded.

⇒	If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the unlock relay.

22. If all circuits test normal, test or replace the inoperative rear door latch assembly.

Door Open Switch Malfunction - Front

1. Ignition OFF, disconnect the harness connector at the inoperative front door latch assembly.
2. Ignition OFF, scan tool OFF, test for less than 10.0 ohms of resistance between the ground circuit 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 Open Switch parameter is INACTIVE.

⇒	If the scan tool displays ACTIVE, test the door open switch signal circuit for a short to ground. If the circuit tests normal, replace the appropriate door control module.

4. Install a 3-A fused jumper wire between the door open switch signal circuit and ground. Verify the scan tool door open switch parameter is ACTIVE.

⇒	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 appropriate door control module.

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

Door Open Switch Malfunction - Rear

1. Ignition OFF, disconnect the harness connector at the inoperative rear door latch assembly.
2. Ignition OFF, scan tool OFF, test for less than 5.0 ohms of resistance between the ground circuit and ground.

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

3. Ignition OFF, all other doors closed, verify the interior lights are OFF.

⇒	If the interior lights are illuminated, test the door open switch signal circuit for a short to ground. If the circuit tests normal, replace the BCM.

4. Install a 3-A fused jumper wire between the door open switch signal circuit and ground. Verify the interior lights are illuminated.

⇒	If the interior lights are not illuminated, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.