The body control module (BCM) receives battery voltage from the CTSY/RF TRN fuse in order to supply power to the courtesy lamps. The BCM applies this voltage to the courtesy lamps through the courtesy lamp supply voltage circuits. When any door is opened, the door open switch contacts close and the BCM receives a door-open signal. If the BCM receives a door lock or unlock signal, the BCM will activate the courtesy lamp supply voltage circuit, providing battery voltage to the dome lamps and the left and right footwell courtesy lamps. The courtesy lamps can be manually activated by placing the interior lamp switch in the DOME position. For more detailed information concerning courtesy lamp operation refer to Interior Lighting Systems Description and Operation.

The BCM receives battery voltage from the INT LAMPS fuse in order to supply power to the inadvertent courtesy lamps. Inadvertent power courtesy lamp feature provides a similar function for the interior lamps as a retained accessory power feature. The BCM will energize the courtesy lamps supply voltage circuit when the BCM is in the active state (awake). When the inadvertent power courtesy lamps supply voltage circuit is energized, it supplies voltage to all the interior lights listed below. The BCM will continue to supply voltage to the interior lamps after the ignition is turned OFF so that the interior lamps may be operated.

In the event that any of these lamps were to remain illuminated for a period of more than 20 minutes with the ignition switch in the OFF position and no BCM input activity, the BCM will deactivate the inadvertent power supply voltage 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 and all doors closed, observe the scan tool Ctsy. Lamp Actv. Reason parameter while turning the dome lamp switch ON and OFF. The parameter should change between Off and Manual.

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

2. Observe the scan tool Driver Door Open Sw. parameter 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 -- Front.

3. Observe the scan tool Passenger Door Open Sw. parameter while opening and closing the front 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 -- Front.

4. Open each rear door one at a time and observe the courtesy lamps. The courtesy lamps should illuminated when each rear door is opened.

⇒	If the courtesy lamps do not illuminate, refer to Door Open Switch Malfunction - Rear.

5. If all scan tool parameters test normal, refer to the appropriate diagnostic procedure listed below.

•	Courtesy Lamps Malfunction

•	Inadvertent Power Courtesy Lamps Malfunction

Dome Lamp Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Verify that a test lamp illuminates between the ground circuit terminal 8 and B+.

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

3. Ignition ON, all doors closed, verify the scan tool Ctsy. Lamp Actv. Reason parameter is Off or Door Closed.

⇒	If not the specified value, test the signal circuit terminal 12 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 12 and ground. Verify the scan tool Ctsy. Lamp Actv. Reason parameter is Manual.

⇒	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.

Door Open Switch Malfunction - Front

1. Ignition OFF, disconnect the harness connector at the inoperative driver door latch assembly.
2. Verify that a test lamp illuminates between the appropriate low reference circuit terminal listed below and B+.

•	Left front door latch assembly terminal 4

•	Right front door latch assembly terminal 1

⇒	If the test lamp does not illuminate, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the appropriate door control module.

3. Ignition ON, verify the appropriate scan tool Door Open Sw. parameter is Inactive.

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

•	Left front door latch assembly terminal 1

•	Right front door latch assembly terminal 4

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

•	Left front door latch assembly terminal 1

•	Right front door latch assembly terminal 4

⇒	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 door control module.

5. If all circuits test normal, test or replace the inoperative door latch assembly.

Door Open Switch Malfunction - Rear

1. Ignition OFF, disconnect the harness connector at the inoperative rear door lock assembly.
2. Test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground.

•	Left rear door latch terminal 6

•	Right rear door latch terminal 3

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

3. Ignition ON, all doors CLOSED, verify the scan tool Ctsy. Lamp Actv. Reason. parameter is Door Closed.

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

•	Left rear door latch terminal 4

•	Right rear door latch terminal 1

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

•	Left rear door latch terminal 4

•	Right rear door latch terminal 1

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

5. If all circuits test normal, test or replace the appropriate door latch assembly.

Courtesy Lamps Malfunction

1. Ignition OFF, disconnect the X3 and X4 harness connectors at the BCM.
2. Verify that a test lamp illuminates between the B+ circuit terminals listed below and ground.

•	Terminal 2 X3

•	Terminal 2 X4

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

3. Connect the X3 and X4 harness connectors at the BCM.
4. Disconnect the harness connector at the inoperative courtesy lamp.
5. Test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground.

•	Left or right roof rail reading lamp terminal B

•	Overhead console lamp terminal A

•	Left or right footwell courtesy lamp terminal B

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

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

•	Left or right roof rail reading lamp terminal A

•	Overhead console lamp terminal B

•	Left or right footwell courtesy lamp terminal A

7. Command the Courtesy Lamp 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.

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

Inadvertent Power Courtesy Lamps Malfunction

1. Ignition OFF, disconnect the X3 harness connector at the BCM.
2. Verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.

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

3. Connect the X# harness connector at the BCM.
4. Disconnect the harness connector at the inoperative courtesy lamp.
5. Test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground.

•	Rear compartment courtesy lamp terminal B

•	LF or RF vanity mirror terminal B

•	Left or right roof rail reading lamp terminal B

•	I/P compartment lamp terminal B

•	Overhead console lamp terminal A

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

6. Ignition ON, verify that a test lamp illuminates between the appropriate control circuit terminal listed below and ground.

•	Rear compartment courtesy lamp terminal C

•	LF or RF vanity mirror terminal A

•	Left or right roof rail reading lamp terminal C

•	I/P compartment lamp terminal A

•	Overhead console lamp terminal C

⇒	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.

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

Door Open Switch Test

1. Ignition OFF, remove the appropriate door lock actuator.
2. Test for infinite resistance between the appropriate signal and low reference terminals listed below with the switch in the open position.

•	Driver door -- signal terminal 1 and low reference terminal 4

•	Passenger door -- signal terminal 4 and low reference terminal 1

•	Left rear door -- signal terminal 1 and ground terminal 4

•	Right rear door -- signal terminal 4 and ground terminal 1

⇒	If not the specified value, replace the appropriate door lock actuator.

3. Test for less than 2 ohms between the appropriate signal and ground terminals listed below with the switch in the closed position.

•	Driver door -- signal terminal 1 and low reference terminal 4

•	Passenger door -- signal terminal 4 and low reference terminal 1

•	Left rear door -- signal terminal 1 and ground terminal 4

•	Right rear door -- signal terminal 4 and ground terminal 1

⇒	If greater than the specified range, replace the appropriate door lock actuator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.