The body control module (BCM) applies battery voltage to the courtesy lamps through 2 separately controlled courtesy lamp supply voltage circuits. When any door is opened, the door ajar switch contacts close and the BCM receives a door-ajar input. If the BCM receives a door lock or unlock input or a rear hatch open input, the BCM will activate the courtesy lamp supply voltage circuits, providing battery voltage to the dome lamp, ignition key cylinder lamp, cargo lamps, and courtesy lamps. In the event that any of these lamps were to remain illuminated for more than 20 minutes with the ignition switch in the OFF position, the BCM will deactivate the courtesy lamp control circuits to prevent a total battery discharge condition.

Schematic Reference

Interior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Interior Lighting Systems Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, doors CLOSED, observe the scan tool Interior Lamp Activation Reason parameter while turning the courtesy lamp defeat switch ON and OFF. The parameter should change between Off and Manual Defeat.

⇒	If the parameter does not change between the commanded states, refer to Dome Lamp Defeat Switch Malfunction.

2. Ignition ON, courtesy lamp defeat switch OFF, observe the scan tool Interior Lamp Activation Reason parameter while opening and closing each door. The parameter should change between Door Open and Door Closed.

⇒	If the parameter does not change as each door is opened and closed, refer to Door Ajar Indicator Malfunction.

3. Operate the dome lamp switch On and Off. The dome lamps should turn On and Off as the switch is activated.

⇒	If the dome lamps do not turn On and Off as the switch is activated, refer to Dome Lamp Switch Malfunction.

4. Command the Interior Lamp Test ON and OFF with a scan tool. The courtesy lamps should turn ON and OFF when changing between the commanded states.

⇒	If the courtesy lamps do not turn On and Off when commanded, refer to Courtesy Lamps Malfunction.

Dome Lamp Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the dome lamp.
2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5 ohms between the ground circuit terminal 10 and ground.

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

3. Ignition ON, verify that a test lamp does not illuminate between the signal circuit terminal 2 and ground.

⇒	If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.

4. Test for B+ between the signal circuit terminal 2 and ground.

⇒	If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

5. If all circuits test normal, replace the dome lamp.

Dome Lamp Defeat Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the dome lamp.
2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5 ohms between the ground circuit terminal 10 and ground.

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

3. Ignition ON, verify that a test lamp does not illuminate between the signal circuit terminal 7 and ground.

⇒	If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.

4. Test for B+ between the signal circuit terminal 7 and ground.

⇒	If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

5. If all circuits test normal, replace the dome lamp.

Courtesy Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative courtesy lamp.
2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground.

•	Dome lamp - front terminal 10

•	Ignition key cylinder lamp terminal B

•	Cargo lamp - left terminal 2

•	Cargo lamp - right terminal 2

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

3. Connect a test lamp between the appropriate control circuit terminal listed below and ground.

•	Dome lamp - terminal 4

•	Ignition key cylinder lamp terminal A

•	Cargo lamp - left terminal 1

•	Cargo lamp - right terminal 1

4. Command the Interior Lamp Test 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 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.

5. If all circuits test normal, replace the inoperative courtesy lamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.