The body control module (BCM) applies battery voltage to the courtesy lamps through the courtesy lamps high control circuit. When any door is opened, the door ajar switch contacts close and the BCM receives a door-open input. If the BCM receives a door lock or unlock input or a rear hatch open input, the BCM will activate the courtesy lamp high control circuit, providing battery voltage to all of the dome lamps, reading lamps, rear compartment lamp, and vanity mirror 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 high control circuit 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, observe the scan tool Driver Door Ajar Sw. parameter while opening and closing the driver door. The parameter should change between DOOR CLOSED and DOOR AJAR.

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

2. Observe the scan tool Door Ajar Switch parameter while opening and closing the front passenger and each rear door one at a time. The parameter should change between DOOR CLOSED and DOOR AJAR.

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

3. Observe the scan tool Trunk Ajar Switch parameter while opening and closing the rear compartment lid. The parameter should change between TRUNK CLOSED and TRUNK AJAR.

⇒	If the reading does not change as the rear compartment is opened and closed, refer to Trunk Ajar Indicator Malfunction .

4. 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 illuminate when commanded, refer to Overhead Illuminated Entry Lamps Malfunction.

5. Rear compartment OPEN, command the Interior Lamps ON and OFF with a scan tool. The rear compartment lamp should turn ON and OFF when changing between the commanded states.

⇒	If the rear compartment lamp does not illuminate when commanded, refer to Rear Compartment Lamp Malfunction.

6. Turn the front and rear reading lamps ON and OFF. The lamps should turn ON and OFF when activated.

⇒	If the reading lamps do not turn ON and OFF, refer to Reading Lamps Malfunction.

Overhead Illuminated Entry Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative courtesy/reading lamp assembly.
2. Connect a test lamp between the appropriate control circuit terminal listed below and ground.

•	Dome/reading lamps control terminal D

•	Overhead console courtesy/reading lamp control terminal B - with C95

•	Vanity mirror lamp - left control terminal A

•	Vanity mirror lamp - right control terminal A

3. 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 OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.

4. Connect a test lamp between B+ and the appropriate control circuit terminal listed below.

•	Dome/reading lamps control terminal B

•	Overhead console courtesy/reading lamp control terminal C - with C95

5. Command the Inadvertent Power 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 OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

⇒	If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.

6. If all circuits test normal, replace the inoperative courtesy/reading lamp assembly.

Reading Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative courtesy/reading lamp assembly.
2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal A and ground.

⇒	If greater than the specified value, 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/reading lamps control terminal D

•	Overhead console courtesy/reading lamp control terminal B - with C95

4. 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 OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.

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

Rear Compartment Lamp Malfunction

1. Ignition OFF, disconnect the harness connector at the rear compartment lamp.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the control circuit terminal B.

⇒	If the test lamp does not illuminate, test the control circuit for a short to voltage or an open/high resistance.

3. Ignition OFF, verify that a test lamp illuminates between the control circuit terminal C and ground.

⇒	If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

4. If all circuits test normal, replace the rear compartment courtesy lamp.

Vanity Mirror Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative vanity mirror.
2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal B and ground.

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

3. Ignition ON, verify a test lamp illuminates between the control circuit terminal A and ground.
4. Connect a test lamp between the control circuit terminal A and ground.
5. 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 OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.

6. If all circuits test normal, replace the inoperative vanity mirror.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.