The BCM 3 fuse, located in the underhood fuse block, supplies battery voltage to the body control module (BCM). The BCM applies this voltage to the courtesy lamps through the courtesy lamp supply voltage circuit. When any door is opened, the door open switch contacts close and the BCM receives a door-open input. If the BCM receives a door lock or unlock input, the BCM will activate the courtesy lamp supply voltage circuit, providing battery voltage to the dome lamp and instrument panel (I/P) courtesy lamps. The courtesy lamps can be manually activated by placing the interior lamp switch in the DOME position.

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 from the BCM 2 fuse located in the underhood fuse block, 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, observe the scan tool Doors, 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 Circuit Test - Driver.

2. 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 Circuit Test - Passenger.

3. Observe the scan tool Ctsy. Lamp Actv. Reason parameter while opening and closing the cargo door. The reading should change between Door Open and Off.

⇒	If the Ctsy. Lamp Actv. Reason. parameter does not change between Door Open and Off, refer to Door Open Switch Circuit Test - Cargo.

4. 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 Circuit Test.

5. Observe the scan tool Ctsy. Lamp Reason parameter while pressing the courtesy lamp defeat switch. The reading should change between Off and Manual Defeat.

⇒	If the Ctsy. Lamp Actv. Reason parameter does not change between Off and Manual Defeat, refer to Dome Lamp Switch Circuit Test.

6. If all scan tool parameters test normal, refer to the appropriate circuit test listed below:

•	Dome Lamp Circuit Test

•	Inadvertent Power Courtesy Lamps Circuit Test

Door Open Switch Circuit Test - Driver

1. Ignition OFF, disconnect the X1 harness connector at the driver door lock.
2. Verify that a test lamp illuminates between the ground circuit terminal D and B+.

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

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

⇒	If not the specified value, test the signal circuit terminal A 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 A and ground. Verify the scan tool Driver Door Open Sw. parameter is Open.

⇒	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 door lock.

Door Open Switch Circuit Test - Passenger

1. Ignition OFF, disconnect the X1 harness connector at the passenger door lock.
2. Verify that a test lamp illuminates between the ground circuit terminal A and B+.

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

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

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

4. Connect a 3A fused jumper wire between the signal circuit terminal D and ground. Verify the scan tool Passenger Door Open Sw. parameter is Open.

⇒	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 door lock.

Door Open Switch Circuit Test - Cargo

1. Ignition OFF, disconnect the X1 harness connector at the cargo door lock.
2. Verify that a test lamp illuminates between the ground circuit terminal A and B+.

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

3. Ignition ON, verify the scan tool Ctsy. Lamp Actv. Reason parameter is Off.

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

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

⇒	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 cargo door lock.

Dome Lamp Switch Circuit 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 with all doors closed, verify the scan tool Ctsy. Lamp Actv. Reason parameter is Off.

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

•	Terminal 9

•	Terminal 12

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. Install a 3A fused jumper wire between the signal circuit terminal 9 and ground. Verify the scan tool Ctsy. Lamp Actv. Reason parameter is Manual Defeat.

⇒	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.

6. If all circuits test normal, test or replace the headlamp switch.

Dome Lamp Circuit Test

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

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

3. Connect a test lamp between the control circuit terminal A and ground.
4. 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.

5. If all circuits test normal, test or replace the dome lamp bulb.

Inadvertent Power Courtesy Lamps Circuit Test

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

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

3. Ignition ON, verify that a test lamp illuminates between the appropriate B+ circuit terminal listed below and ground.

•	Courtesy/Reading Lamp terminal C

•	Left or Right Sunshade Mirror terminal A

•	Underhood Lamp terminal A

⇒	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, replace the BCM.

4. If all circuits test normal, test or replace the lamp bulb.

Door Open Switch Test

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

•	Driver door signal terminal A and ground terminal D

•	Front passenger door signal terminal D and ground terminal A

•	Cargo door signal terminal D and ground terminal A

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

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 A and ground terminal D

•	Front passenger door signal terminal D and ground terminal A

•	Cargo door signal terminal D and ground terminal A

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.