When a courtesy lamp request is seen, ignition voltage is supplied to each of the courtesy lamps by the body control module (BCM) via the courtesy lamp supply voltage circuit. The courtesy lamp supply voltage circuit controls the following lamps:

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

Ignition ON, verify the door ajar indicator is illuminated when each of the vehicle doors are open.

1. Verify the door ajar indicator is illuminated when each of the vehicle doors are open.

⇒	If opening any of the vehicle doors does not result in the door ajar indicator illuminating, refer to Symptoms - Vehicle Access .

2. Ignition ON, observe the scan tool Interior Light Switch parameter while cycling the dome lamp switch ON and OFF. The parameter should change between Off and On when changing between the commanded states.

⇒	If the parameter does not cycle between the specified value, refer to Dome Lamp Switch Circuit Malfunction.

3. Command the Interior Lamps 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, refer to Courtesy Lamp Circuit Malfunction.

4. With the driver door open, observe the courtesy lamps while cycling the dome lamp defeat switch ON and OFF. The courtesy lamps should turn ON and OFF when changing between the commanded states.

⇒	If the courtesy lamps do not turn ON and OFF, refer to Dome Lamp Defeat Switch Circuit Malfunction.

Dome Lamp Switch Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Test for less than 10 ohms between the ground circuit terminal 17 and ground.

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

3. Ignition ON, verify the scan tool Interior Light Switch parameter is Off.

⇒	If not the specified value, test the signal circuit terminal 2 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 2 and ground. Verify the scan tool Interior Light Switch parameter is On.

⇒	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 headlamp switch.

Courtesy Lamp Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the appropriate courtesy lamp.
2. Test for less than 10 ohms between the ground circuit terminal B and ground:

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

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

•	I/P Courtesy Lamp - Terminal A

•	Dome/Reading Lamp - Terminal C

•	Reading Lamps - Terminal C

4. Ignition ON, command the Interior Lamps 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, test or replace the appropriate courtesy lamp bulb.

Courtesy Lamp Circuit Malfunction

1. Driver door open, disconnect the harness connector at the headlamp switch. Verify the courtesy lamps are illuminated.

⇒	If the courtesy lamps are not illuminated, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the BCM.

2. Install a 3A jumper wire between the signal circuit terminal 4 and ground. Verify the courtesy lamps are not illuminated.

⇒	If the courtesy lamps are illuminated, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

3. If all circuits test normal, test or replace the headlamp switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.