The DR LCK fuse supplies battery positive voltage to the I/P fuse block for the door lock system. The BCM supplies and monitors a reference voltage to the door lock switch through the door lock switch lock/unlock signal circuit. The door lock switch also receives a constant ground source. If a door lock switch is placed in the lock position or unlock position, the reference voltage is taken directly to ground and the BCM detects 0.0 volts on the signal circuit.

The BCM, upon receipt of a door lock switch lock or unlock signal, will switch the appropriate door lock actuator control circuits to battery positive voltage. The opposing side of the door lock actuators are connected to ground internally within the BCM through the other door lock actuator control circuit and the doors will lock or unlock appropriately.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

Scan Tool Reference

1. Ignition ON, observe the Driver Door Lock Sw or Psgr Door Lock Sw and Driver Door Unlock Sw or Psgr Door Unlock Sw parameters while pressing the appropriate door lock switch. The reading should change between Active and Inactive.

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

2. Command the Driver Door and Passenger Doors to Lock and Unlock with the scan tool, the doors should Lock and Unlock.

⇒	If the any door does not Lock and Unlock when changing between commanded states, refer to Door Lock Malfunction.

Door Lock Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the appropriate door lock switch.
2. Test for less than 1.0 ohm for resistance between the ground circuit terminal 3 and ground.

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

3. Ignition ON, verify the appropriate scan tool Door Lock Sw parameter is Inactive.

⇒	If not the specified value, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the BCM.

4. Verify the appropriate scan tool Door Unlock Sw parameter is Inactive.

⇒	If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the BCM.

5. Install a 3 amp fused jumper wire between the Unlock signal circuit terminal 2 and ground. Verify the appropriate scan tool Door Unlock Sw 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 BCM.

6. Install a 3 amp fused jumper wire between the lock signal circuit terminal 1 and ground. Verify the appropriate scan tool Lock Sw 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 BCM.

Door Lock Malfunction

1. Ignition OFF, disconnect the harness connector C1 at the I/P fuse block.
2. Test for less than 1.0 ohm of resistance between the ground circuit terminal 25 and ground.

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

3. Disconnect the harness connector C2 at the I/P fuse block.
4. Ignition ON, connect a test lamp between the B+ circuit terminal 3 and ground, the test lamp should turn ON.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or and open/high resistance.

5. Ignition OFF, disconnect the harness connector C3 at the I/P fuse block.
6. Connect a test lamp between the control circuit terminal 42 and ground.
7. Ignition ON, command the Lock Rear Doors ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp does 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.

8. Connect a test lamp between the control circuit terminal 8 and B+.
9. Command the Driver Door Unlock ON and OFF 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 and open/high resistance. If the circuit tests normal, replace the BCM

10. Connect a test lamp between the control circuit terminal 41 and B+.
11. Command the Unlock Rear Doors ON and OFF 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 and open/high resistance. If the circuit tests normal, replace the BCM.

12. Ignition OFF, connect the harness connectors C3, C2 and C1 at the I/P fuse block.
13. Disconnect the harness connector at the appropriate door latch.
14. Test for less than 1.0 ohm of resistance between the control circuit terminal of the appropriate door latch listed below and ground:

•	Driver and LR door latch control circuit terminal 2

•	Passenger and RR door latch control circuit terminal 5

⇒	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 I/P fuse block.

15. Test for less than 1.0 ohm of resistance between the control circuit terminal of the appropriate door latch listed below and ground:

•	Driver door latch control circuit terminal 3

•	Passenger and RR door latch control circuit terminal 6

•	LR door latch control circuit terminal 1

⇒	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 I/P Fuse Block

16. Connect a test lamp between two control circuit terminals of the appropriate door latch listed below:

•	Driver door latch control circuit terminal 2 and control circuit terminal 3

•	Passenger and RR door latch control circuit terminal 5 and control circuit terminal 6

•	LR door latch control circuit terminal 2 and control circuit terminal 1

17. Ignition ON, command the Door Lock to LOCK and UNLOCK with a scan tool. The test lamp should turn ON when commanding the LOCK and UNLOCK states.

⇒	If the test lamp remains OFF during either of the commands and the DR/LCK fuse is good, test for a short to ground on either control circuit. If the circuits test normal, replace the I/P fuse block.

⇒	If the test lamp is always OFF and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the door latch.

18. If all circuits test normal, test or replace the appropriate door latch.

Door Lock Switch Test

1. Ignition OFF, disconnect the harness connector at the applicable door lock switch.
2. Test for infinite resistance between the signal terminals 2 and 1 and the ground terminal 3 with the switch in the open position.

⇒	If less than infinite resistance, replace the applicable door lock switch.

3. Test for less than 2 ohms of resistance between the signal terminal 1 and the ground terminal 3 with the switch in the lock position.

⇒	If greater than 2 ohms, replace the applicable door lock switch.

4. Test for less than 2 ohms of resistance between the signal terminal 2 and the ground terminal 3 with the switch in the unlock position.

⇒	If greater than 2 ohms, replace the applicable door lock switch.

Door Latch Assembly

1. Install a 20A fused jumper wire between the control terminal and 12 volts. Install a jumper wire between the ground terminal and ground.
2. Verify the actuator turns ON and OFF.

⇒	If the function does not perform as specified, replace the applicable door latch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.