Courtesy Lamps Malfunction
Courtesy Lamps Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The courtesy lamps are controlled by the body control module (BCM). Inputs from the dome lamp switch and the door ajar switches are monitored by the BCM. When a door ajar switch is closed, or the dome lamp switch is turned to the ON position, the BCM supplies the ground for the courtesy lamps. The BCM also supplies the voltage for the courtesy lamps.
Diagnostic Aids
* Check for the proper operation of the courtesy lamp bulbs.
* Check the position of the dome lamp switch.
Circuit/System Verification
1. Ignition ON, courtesy defeat switch in the OFF position.
2. Open and close each door while observing the scan tool Ctsy. Lamp Actv. Reason parameter. The parameter should change between Door Open and Off.
^ If the parameter is always Door Open or always Off, refer to
^ If the parameter is always Manual Defeat, refer to Courtesy Defeat Switch Malfunction.
3. Courtesy lamps switch in the OFF position, all doors closed.
4. Verify the scan tool Ctsy. Lamp Actv. Reason parameter is Off.
^ If the parameter is Manual, refer to Courtesy Lamps Switch Malfunction.
5. Courtesy lamps switch in the ON position, verify the courtesy lamps illuminate.
^ If only one courtesy lamp is inoperative, refer to Courtesy Lamp Inoperative - One
^ If all courtesy lamps are inoperative, refer to Courtesy Lamps Switch Malfunction.
6. Open the driver door.
7. Verify the courtesy lamps illuminate.
^ If the courtesy lamps do not illuminate, refer to Courtesy Lamps Inoperative.
8. Refer to Courtesy Lamps Always On.
Circuit/System Testing
Courtesy Defeat 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 or short to voltage.
3. Ignition ON, all doors closed.
4. Verify the the scan tool Ctsy. Lamp Actv. Reason parameter is Off.
^ If the parameter is Manual Defeat, test the courtesy defeat signal circuit terminal 25 for a short to ground. If the circuit tests normal, replace the BCM.
5. Connect a 3A fused jumper wire between the courtesy defeat signal circuit terminal 25 and ground.
6. Verify the the scan tool Ctsy. Lamp Actv. Reason parameter is Manual Defeat.
^ If not the specified value, test the signal circuit for an open/high resistance or short to voltage. If the circuit tests normal, replace the BCM.
7. If all circuits test normal, replace the headlamp switch.
Courtesy Lamps 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 or short to voltage.
3. Ignition ON, all doors closed.
4. Verify the the scan tool Ctsy. Lamp Actv. Reason parameter is Off.
^ If the parameter is Manual, test the courtesy lamps on signal circuit terminal 12 for a short to ground. If the circuit tests normal, replace the BCM.
5. Connect a 3A fused jumper wire between the courtesy lamps on signal circuit terminal 12 and ground.
6. Verify the the scan tool Ctsy. Lamp Actv. Reason parameter is Manual.
^ If not the specified value, test the signal circuit for an open/high resistance or short to voltage. If the circuit tests normal, replace the BCM.
7. If all circuits test normal, replace the headlamp switch.
Courtesy Lamp Inoperative - One
1. Ignition OFF, disconnect the harness connector at the inoperative courtesy lamp.
2. Verify that a test lamp illuminates between the ground circuit listed below and B+.
* Liftgate courtesy lamps - terminal 1
* All other courtesy lamps - terminal B
^ If the test lamp does not illuminate, test the ground circuit for an open/high resistance or short to voltage.
3. Place the courtesy lamp switch in the ON position.
4. Verify that a test lamp illuminates between the courtesy lamp voltage supply circuit listed below and ground.
* Liftgate courtesy lamps - terminal 2
* All other courtesy lamps - terminal A
^ If the test lamp does not illuminate, test the supply circuit for an open/high resistance or short to ground.
5. If all circuits test normal, replace the inoperative courtesy lamp.
Courtesy Lamps Inoperative
Test the courtesy lamps supply voltage circuit for an open/high resistance or short to ground. If the the circuit tests normal, replace the BCM.
Courtesy Lamps Always On
Test the courtesy lamps supply voltage circuit for a short to voltage. If the the circuit tests normal, replace the BCM.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Front Side Door Latch Replacement
* Rear Side Door Latch Replacement