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 control circuit. The courtesy lamp control 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

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

•	Courtesy/Reading Lamp terminal A

•	Vanity Mirror Lamp terminal B

•	Roof Rail Reading Lamp terminal A

•	Cargo Lamp terminal A

⇒	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 and ground:

•	Courtesy/Reading Lamp terminal C

•	Vanity Mirror Lamp terminal A

•	Roof Rail Reading Lamp terminal B

•	Cargo Lamp terminal B

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.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.