Power Door Locks Inoperative - Front RPO AN3/DL3

The driver and passenger door lock and side window switches are integrated control module switch assemblies. The DDS and PDS door lock switches are normally open, 2 position rocker type switches, with detents for lock and unlock. The DDS and PDS are directly connected to the respective door lock actuator through the door lock actuator control circuits. When a door lock or unlock function is activated from the DDS or PDS a GMLAN lock or unlock command is sent to the other door switch and body control module.

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

Front Power Door Locks Inoperative

1. Install a scan tool and display the Driver Door Switch Outputs data list.
2. Verify that the door lock actuator command parameter displays Off, Lock, and Unlock while the driver door lock switch is operated from lock to unlock.

⇒	If the lock actuator parameter is incorrect, replace the DDS.

3. Display the Passenger Door Switch Outputs data list.
4. Verify that the door lock actuator command parameter displays Off, Lock, and Unlock while the passenger door lock switch is operated from lock to unlock.

⇒	If the lock actuator parameter is incorrect, replace the PDS.

5. Disconnect the affected door latch connector, and connect a test lamp across the lock actuator control circuit terminals.
6. Verify that the test lamp illuminates while the lock switch is operated to lock and unlock.

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

7. If the circuits test normal replace the affected door switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Power Door Locks Inoperative - Front RPO AU3 without AN3/DL3

The power door locks are controlled by the body control module (BCM) through lock and unlock printed circuit board relays in the IP fuse block. The driver and passenger door lock switches are normally open, 2 position rocker type switches, with detents for lock and unlock. The lock and unlock switch signal circuits are referenced from battery voltage by the BCM and when a door lock or unlock switch is pressed the signal circuit is closed to ground through the switch contacts and BCM determines the signal is active. The unlock relays are controlled by the BCM through driver door and passenger door low side drive control circuits and the lock relays are controlled through a single high side drive control circuit. During lock or unlock operation, battery voltage will be supplied to the lock actuators through the energized relays and grounded through the de-energized relays.

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. Verify that the BCM door lock switch parameters display Idle, Lock, and Unlock while operating the driver and passenger door lock switches to lock and unlock.

⇒	If either of the scan tool parameters do not match the actual switch positions perform the Door Lock Switch Circuit Test.

2. Verify that a test lamp connected to ground illuminates on the supply side of the lock fuses 1 and 2 when a lock switch is activated.

⇒	If the test lamp does not illuminate at one or both fuses perform the Door Lock Relay Control Circuit Test.

⇒	If the test lamp illuminates at both fuses perform the Door Lock Actuator Circuit Test.

3. Verify that a test lamp connected to ground illuminates on the supply side of the unlock DRV fuse when an unlock switch is activated.

⇒	If the test lamp does not illuminate at any of the fuses perform the Driver Door Unlock Relay Control Circuit Test.

⇒	If the test lamp illuminates perform the Door Lock Actuator Circuit Test.

4. Verify that a test lamp connected to ground illuminates on the supply side of the unlock fuses 1 and 2 when a unlock switch is activated.

⇒	If the test lamp does not illuminate at one or both fuses perform the Door Lock Relay Control Circuit Test.

⇒	If the test lamp illuminates at both fuses perform the Door Lock Actuator Circuit Test.

Door Lock Switch Circuit Test

1. Disconnect the affected door lock switch and verify that the scan tool switch parameter displays Idle.

⇒	If the parameter displayed is Lock or Unlock test the affected switch signal circuit for a short to ground. If the circuit tests normal replace the BCM.

2. Verify less than 1 ohm or resistance from the ground circuit terminal B to ground.

⇒	If the resistance is greater than the specified value repair the ground circuit for an open/high resistance.

3. Connect a fused jumper wire from the lock switch signal circuit terminal D to ground and verify that the scan tool switch parameter displays Lock.

⇒	If the parameter displayed is not Lock test the lock switch signal circuit for an open/high resistance. If the circuit tests normal replace the BCM.

4. Connect a fused jumper wire from the unlock switch signal circuit terminal E to ground and verify that the scan tool switch parameter displays Unlock.

⇒	If the parameter displayed is not Unlock test the unlock switch signal circuit for an open/high resistance. If the circuit tests normal replace the BCM.

5. If the circuits test normal replace the affected door lock switch.

Door Lock Relay Control Circuit Test

1. Verify that a test lamp connected to battery voltage illuminates when connected to the supply side of the lock 1 and 2 fuses in the IP fuse block.

⇒	If the test lamp does not illuminate test the lock/unlock relay ground circuit for an open/high resistance. If the circuit tests normal replace the IP fuse block.

2. Disconnect the BCM connector C7.
3. Verify that all of the door lock actuators lock when a fused jumper wire is connected to the door lock relay control circuit terminal 7 and briefly applied to battery voltage.

⇒	If all of the door lock actuators do not lock, test the door lock relay control circuit for an open/high resistance. If the circuit tests normal replace the IP fuse block.

⇒	If only the front or rear door lock actuators do not lock replace the IP fuse block.

4. If the circuits test normal replace the BCM.

Driver Door Unlock Relay Control Circuit Test

1. Verify that a test lamp connected to battery voltage illuminates when connected to the supply side of the DRV unlock fuse in the IP fuse block.

⇒	If the test lamp does not illuminate test the IP fuse block ground circuit for an open/high resistance. If the circuit tests normal replace the IP fuse block.

2. Disconnect the BCM connector C7.
3. Verify that the driver door lock actuator unlocks when a fused jumper wire is connected to the driver door unlock relay control circuit terminal 6 and briefly applied to ground.

⇒	If the driver door lock actuator does not unlock, test the driver door unlock relay control circuit for an open/high resistance. If the circuit tests normal replace the IP fuse block.

4. If the circuits test normal replace the BCM.

Passenger Door Unlock Relay Control Circuit Test

1. Verify that a test lamp connected to battery voltage illuminates when connected to the supply side of the unlock 1 and 2 fuses in the IP fuse block.

⇒	If the test lamp does not illuminate test the IP fuse block ground circuit for an open/high resistance. If the circuit tests normal replace the IP fuse block.

2. Disconnect the BCM connector C7.
3. Verify that all of the passenger door lock actuators unlock when a fused jumper wire is connected to the passenger door unlock relay control circuit terminal 9 and briefly applied to ground.

⇒	If the passenger door lock actuators do not unlock, test the passenger door unlock relay control circuit for an open/high resistance. If the circuit tests normal replace the IP fuse block.

4. If the circuits test normal replace the BCM.

Door Lock Actuator Circuit Test

1. Disconnect the affected door latch connector and connect a test lamp across the lock actuator control circuit terminals.
2. Verify that the test lamp illuminates briefly when a lock and unlock switch is activated.

⇒	If the test lamp does not illuminate in both switch positions test the lock actuator control circuits for an open/high resistance or short to ground. If the circuits test normal replace the IP fuse block.

3. If the circuits test normal replace the affected door latch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.