The 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

Lighting Systems Connector End Views

Electrical Information Reference

Scan Tool Reference

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 reading should change between OFF and MANUAL.

⇒	If the Ctsy. Lamp Actv. Reason parameter does not change between OFF and MANUAL, refer to Dome Lamp Switch Test.

2. Observe the scan tool Driver Door Open Sw. parameter while opening and closing the driver door. The reading should change between Open and Closed.

⇒	If the Driver Door Open Sw. parameter does not change between Open and Closed, refer to Door Open Switch Test-Front.

3. Observe the scan tool Passenger Door Open Sw. parameter while opening and closing the front passenger door. The reading should change between Open and Closed.

⇒	If the Passenger Door Open Sw. parameter does not change between Open and Closed, refer to Door Open Switch Test-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 Test-Rear.

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

•	Courtesy Lamp Circuit Test

•	Inadvertent Power Courtesy Lamp Circuit Test

Dome Lamp Switch Test

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 Test - Front

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

•	Left Front Door Lock terminal 4

•	Right Front Door Lock 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 door control module

3. Ignition ON, verify the appropriate scan tool Door Switch 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 Lock terminal 1

•	Right Front Door Lock 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 Switch Door Open Sw. parameter is Open.

•	Left Front Door Lock terminal 1

•	Right Front Door Lock 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 lock assembly.

Door Open Switch Test - Rear

1. Ignition OFF, disconnect the harness connector at the inoperative rear door lock assembly.
2. Test for less than 5.0 ohms of resistance between the appropriate ground circuit terminal listed below and ground.

•	Left Rear Door Lock terminal 4

•	Right Rear Door Lock terminal 1

⇒	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 BCM 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 Lock terminal 1

•	Right Rear Door Lock terminal 4

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

•	Left Rear Door Lock terminal 1

•	Right Rear Door Lock terminal 4

⇒	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 lock assembly.

Courtesy Lamp Circuit Test

1. Ignition OFF, disconnect the (C3, C4) harness connectors at the BCM.
2. Verify that a test lamp illuminates between B+ circuits listed below and ground.

•	Terminal 2 C3

•	Terminal 2 C4

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the related courtesy lamp supply voltage circuits for a short to ground.

3. Ignition OFF, connect the BCM harness connectors.
4. Disconnect the harness connector at the inoperative courtesy lamp lamp.
5. Test for less than 5.0 ohms of resistance 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 supply voltage 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 supply voltage circuit for a short to voltage. If the circuit tests normal, replace the BCM.

⇒	If the test lamp is always OFF, test the supply voltage 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 courtesy lamp bulb.

Inadvertent Power Courtesy Lamps Circuit Test

1. Ignition OFF, disconnect the (C3) 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. If the circuit tests normal and the B+ circuit fuse is open, test the inadvertent power courtesy lamp circuit for a short to ground.

3. Ignition OFF, connect the harness connector at the BCM.
4. Disconnect the harness connector at the inoperative lamp.
5. Test for less than 5.0 ohms of resistance 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 inadvertent power courtesy lamp circuit terminal 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 inadvertent power courtesy lamp 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, replace the inoperative 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 lo 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.