The CTSY/LAMP fuse supplies battery voltage to the body control module (BCM). The BCM applies battery voltage to the courtesy lamps through the courtesy lamp supply voltage circuit. When any door is opened, the jam 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 supply voltage circuit, providing battery voltage to all of the instrument panel (I/P) courtesy lamps, rearview mirror lamps, and rear compartment lamps. The BCM also provides a serial data message to the driver door module (DDM) and passenger door module (PDM) to apply battery voltage to the exterior courtesy 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 ON, observe the scan tool Dome Lamp Switch parameter while pressing and releasing the dome lamp switch. The parameter should CHANGE between Off and On.

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

2. Observe the scan tool LF Door Open Switch parameter located in Keyless/Remote Start Data while opening and closing the driver door. The parameter should change between Open and Closed.

⇒	If the parameter does not change between the commanded states, refer to Door Open Switch Malfunction.

3. Observe the scan tool RF Door Open Switch parameter located in Keyless/Remote Start Data while opening and closing the passenger door. The parameter should change between Open and Closed.

⇒	If the parameter does not change between the commanded states, refer to Door Open Switch Malfunction.

Dome Lamp Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the I/P dimmer switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 1.

⇒	If the test lamp does not illuminate, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the IPC.

3. Ignition ON, verify the scan tool dome lamp switch parameter is OFF.

⇒	If not the specified value, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the IPC.

4. Install a 3A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool dome lamp 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 IPC.

5. If all circuits test normal, test or replace the I/P dimmer switch.

Door Open Switch Malfunction

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

•	Driver door latch ground terminal 8

•	Passenger door latch ground terminal 3

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

3. Ignition ON, verify the scan tool Door Open Switch parameter is Closed.

⇒	If not the specified value, test the appropriate signal circuit terminal listed below for a short to ground. If the circuit tests normal, replace the BCM.

•	Driver door open switch signal terminal 7

•	Passenger door open switch signal terminal 2

4. Install a 3A fused jumper wire between the appropriate signal circuit terminal listed below and ground. Verify the scan tool Door Open Switch parameter is Door Closed.

•	Driver door open switch signal terminal 7

•	Passenger door open switch signal terminal 2

⇒	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 inoperative door latch assembly.

Instrument Panel (I/P) Compartment Lamp Malfunction

1. Ignition OFF, disconnect the harness connector at the I/P compartment lamp.
2. Ignition OFF, test for less than 1 ohm between the ground circuit terminal B 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 illuminates between the control circuit terminal A 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 I/P compartment lamp switch.

Instrument Panel Courtesy Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative courtesy lamp.
2. Ignition OFF, test for less than 1 ohm between the control circuit terminal B and ground.

⇒	If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

3. Ignition ON, verify that a test lamp illuminates between the control circuit terminal A 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. Ignition OFF, connect a test lamp between the control circuit terminal A and the control circuit terminal B.
5. Command the Interior Lamps ON with a scan tool. The test lamp should turn ON for 5 seconds and then turn OFF.

⇒	If the test lampis always ON, test the control circuit terminal B for a short to ground. If the circuit test normal, replace the BCM.

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

Rear Compartment Courtesy Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative rear compartment lamp.
2. Ignition OFF, exterior lamps OFF, rear compartment lid OPEN, test for less than 5 ohms between the ground circuit terminal B and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance, if the circuits test normal, replace the rear compartment lid latch or pull down actuator.

3. Ignition ON, verify that a test lamp illuminates between the control circuit terminal A 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 inoperative rear compartment lamp.

Underhood Lamp Malfunction

1. Ignition OFF, disconnect the harness connector at the underhood lamp.
2. Ignition OFF, test for less than 5 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. Ignition ON, verify that a test lamp illuminates between the control circuit terminal A 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 underhood lamp.

Vanity Mirror Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative vanity mirror.
2. Ignition OFF, scan tool OFF, interior lamps OFF, test for less than 1 ohm between the ground circuit terminal B 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 illuminates between the control circuit terminal A 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 inoperative vanity mirror.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.