The BCM controls the rear door lock actuators through a PCB relay in the IP fuse block. The unlock side of the relay is controlled by the BCM through a low side drive control circuit and the lock side of the relay is controlled through a high side drive control circuit. When the BCM grounds the door unlock control circuit, the unlock relay coil is energized and battery voltage is supplied to the unlock actuator control circuits through the UNLCK 1 and UNLCK 2 fuses. During unlock operation the actuators are grounded through the lock control circuits to the lLCK 1 and LCK 2 fuses and the de-energized lock side of the relay. When the BCM supplies voltage the lock relay control circuit, the lock relay coil is energized and battery voltage is supplied to the lock actuator control circuits through the LCK 1 and LCK 2 fuses. During lock operation the actuators are grounded through the unlock control circuits to the UNLCK 1 and UNLCK 2 fuses and the de-energized unlock side of the relay.

Schematic Reference

Door Lock/Indicator Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Power Door Locks Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for Scan Tool Information

1. Command the Lock Rear Doors and Unlock Rear Doors with a scan tool, the rear doors should perform LOCK and UNLOCK function.

⇒	If a rear door does not LOCK or UNLOCK, refer to Rear Door Lock Malfunction.

2. Command the liftgate to LOCK and UNLOCK by using the driver door lock switch, the liftgate should perform LOCK and UNLOCK function.

⇒	If the liftgate does not LOCK or UNLOCK, refer to Liftgate Lock Malfunction

Rear Door Lock Malfunction

1. Ignition OFF, disconnect the X1 harness connector at the I/P fuse block.
2. Test for less than 1 ohm between the ground circuit terminal E1 and ground.

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

3. Connect the X1 harness connector and disconnect the X3 harness connector at the I/P fuse block.
4. Connect a test lamp between control circuit terminal A2 and ground.
5. Ignition ON, command the Lock Rear Doors with a scan tool. The test lamp should briefly illuminate during the LOCK command.

⇒	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.

6. Connect a test lamp between control circuit terminal A3 and B+.
7. Command Unlock Rear Doors with a scan tool. The test lamp should briefly illuminate during the UNLOCK command.

⇒	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 and open/high resistance. If the circuit tests normal, replace the BCM.

8. Ignition OFF, connect the harness connector at the I/P fuse block. Disconnect the harness connector at the appropriate rear door latch.
9. Ignition ON, connect a test lamp between the appropriate control circuit terminals listed below:

•	Left rear door latch terminals 2 and 3

•	Right rear door latch terminals 5 and 6

10. Command the Lock Rear Doors and Unlock Rear Doors with a scan tool. The test lamp should briefly illuminate when commanding the LOCK and UNLOCK states.

⇒	If the test lamp is always OFF, test either control circuit for a short to ground or an open/high resistance. If the circuit tests normal and the circuit fuse is good, replace the I/P fuse block.

⇒	If the test lamp is always ON, test either control circuit for a short to voltage. If the circuit tests normal, replace the I/P fuse block.

11. If all circuits test normal, test or replace the rear door latch.

Liftgate Lock Malfunction

1. Ignition OFF, disconnect the harness connector at the liftgate door lock actuator.
2. Connect a test lamp between the control circuit terminal A and control circuit terminal B.
3. Ignition ON, command the liftgate door lock actuator to LOCK and UNLOCK by using the driver door lock switch. The test lamp should illuminate during the LOCK and UNLOCK command.

⇒	If the test lamp is always OFF, test either control circuit for a short to ground or an open/high resistance. If the circuit tests normal and the circuit fuse is good, replace the I/P fuse block.

⇒	If the test lamp is always ON, test either control circuit for a short to voltage. If the circuit tests normal, replace the I/P fuse block.

4. If all circuits test normal, test or replace the liftgate door lock actuator.

1. Ignition OFF, disconnect the harness connector at the appropriate door latch.
2. Install a 15A fused jumper wire between one of the control terminals and 12V. Momentarily install a jumper wire between the other control terminal and ground. Reverse the jumper wires at least two times, the door latch should perform the LOCK/ UNLOCK functions.

⇒	If it does not perform as specified, replace the door latch

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.