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 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 OFF, test for less than 10.0 ohms between the door lock actuator lock control circuit terminal and ground.

⇒	If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the appropriate door control module.

3. Ignition OFF, test for less than 10.0 ohms between the door lock actuator unlock control circuit terminal and ground.

⇒	If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the appropriate door control module.

4. Ignition OFF, connect a test lamp between the lock control circuit terminal and unlock control circuit terminal at the door latch harness connector.
5. 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 a short to ground on either control circuit. If the circuits test normal, replace the appropriate door control module.

6. 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 5.0 ohms between the ground circuit terminal R19 and ground.

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

3. Test for less than 5.0 ohms between the ground circuit terminal R20 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 R18 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 R17 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 R16 and ground.
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 5.0 ohms between the ground circuit terminal R34 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 R35 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 R32 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 R33 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 R35 and the control circuit terminal R31.
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 between the lock control circuit terminal at the inoperative rear door latch assembly harness connector 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 between the unlock control circuit terminal at the inoperative rear door latch assembly harness connector 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 at the inoperative rear door latch assembly harness connector 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 at the inoperative rear door latch assembly harness connector 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.

Power Door Locks Deadbolt Malfunction - Front (European)

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

⇒	If greater than the specified range, test the deadbolt control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the appropriate door control module.

3. Ignition OFF, scan tool OFF, test for less than 5.0 ohms between the unlock control circuit terminal and ground.

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

4. Connect a test lamp between the deadbolt lock control circuit terminal and unlock control circuit terminal.
5. Perform the DOOR DEADBOLT LOCK/UNLOCK test with a scan tool. The test lamp should turn ON when performing the DOOR LOCK/UNLOCK test.

⇒	If the test lamp remains OFF during either of the commands, test for a short to ground on either control circuit. If the circuits test normal, replace the appropriate door control module.

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

Power Door Locks Deadbolt Malfunction - Rear (European)

1. Ignition OFF, disconnect the C2 harness connector at the BCM.
2. Ignition OFF, scan tool OFF, test for less than 5.0 ohms between the double lock relay switch B+ circuit terminal D and ground.

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

3. Connect a test lamp between the relay switch B+ circuit terminal D and ground.
4. 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 B+ circuit terminal D for a short to voltage. If the circuit tests normal, replace the lock relay.

⇒	If the test lamp is always OFF, test the B+ circuit terminal D for a short to ground or an open/high resistance. If the circuit tests normal, replace the lock relay.

5. Connect the C2 harness connector at the BCM.
6. Disconnect the harness connector at the inoperative rear door latch assembly.
7. Connect a test lamp between the deadbolt motor control circuit and ground.
8. Command the rear door deadbolts to LOCK with a scan tool. The test lamp should turn ON when commanded to the LOCK position.

⇒	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.

9. Connect a test lamp between the unlock relay switch controlled output circuit and ground.
10. 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 unlock relay.

⇒	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 unlock relay.

11. 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 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 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.