The interior courtesy lamps consist of the dome lamp and the left and right footwell lamps. Battery voltage is supplied to the courtesy lamps by the body control module (BCM) through an inadvertent power supply circuit. In the event that any of these lamps were to remain illuminated for a period of more than 20 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power supply to prevent a total battery discharge condition. Courtesy lamp operation is controlled by the BCM through low side drive control circuits, and any time the inadvertent power supply is active the BCM turns on the courtesy lamps by grounding the control circuits. The BCM will activate the courtesy lamps using inputs from the dome lamp switch on the headlamp switch assembly or any of the door jamb switches. The dome lamp switch signal is monitored from battery voltage by the BCM and when the switch is turned on the signal circuit will be closed to the headlamp switch low reference circuit. The door jamb switch signals are monitored from battery voltage by the BCM and when a door is opened the signal circuit will be grounded through the door jamb switch.

Schematic Reference

Interior Lights Schematics

Connector End View Reference

Lighting Systems Connector End Views

Description and Operation

Interior Lighting Systems Description and Operation

Electrical Information Reference

Scan Tool Reference

1. Verify that the courtesy lamp switch parameter displays active and inactive while operating the dimming control/courtesy lamp switch on and off.

⇒	If the scan tool parameter does not display the correct state in relation to the actual switch position, refer to the courtesy lamp switch circuit test.

2. Verify that the driver door ajar switch parameter displays door open and door closed while opening and closing the driver door.

⇒	If the scan tool parameter does not display the correct state in relation to the actual switch position, refer to the driver door jamb switch circuit test.

3. Verify that the passenger door ajar switch parameter displays door open and door closed while opening and closing the front passenger door and rear passenger doors if equipped.

⇒	If the scan tool parameter does not display the correct state in relation to the actual switch position, refer to the passenger door jamb switch circuit test.

4. If the circuits test normal refer to the courtesy lamp control circuit test.

Courtesy Lamp Switch Circuit Test

1. Disconnect the headlamp switch connector and verify that the courtesy lamp switch parameter displays inactive.

⇒	If the parameter displays active test the switch signal circuit for a short to ground. If the circuit tests normal replace the BCM.

2. If the circuits test normal replace the headlamp switch.

Driver Door Jamb Switch Circuit Test

1. Ignition OFF, disconnect the harness connector at the driver door jamb switch.
2. 2. Test for less than 1 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. Ignition ON, verify the scan tool driver door ajar switch parameter is door closed.

⇒	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. Install a 3A fused jumper wire between the signal circuit terminal 1 and the ground circuit terminal 2. Verify the scan tool driver door ajar switch parameter is door ajar.

⇒	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.

5. If all circuits test normal, test or replace the driver door ajar switch.

Passenger Door Jamb Switch Circuit Test

1. Ignition OFF, disconnect the harness connector at the affected door jamb switch.
2. Test for less than 1 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. Ignition ON, verify the scan tool passenger door ajar switch parameter is door closed.

⇒	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. Install a 3A fused jumper wire between the signal circuit terminal 1 and the ground circuit terminal 2. Verify the scan tool passenger door ajar switch parameter is door ajar.

⇒	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.

5. If all circuits test normal, test or replace the affected door jamb switch.

Courtesy Lamp Switch Test

1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Test for infinite resistance between the signal terminal 11 and the low reference terminal 3 with the courtesy lamp switch in the off position.

⇒	If not the specified value, replace the headlamp switch.

3. Test for less than 1 ohm between the signal terminal 11 and the ground terminal 3 with the courtesy lamp switch in the on position.

⇒	If greater than the specified range, replace the headlamp switch.

Door Jamb Switch Test

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

⇒	If not the specified value, replace the door jamb switch.

3. Test for less than 1 ohm between the signal terminal 1 and the ground terminal 2 with the switch in the closed position.

⇒	If greater than the specified range, replace the door jamb switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.