Courtesy Lamps Malfunction
Courtesy Lamps Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The interior courtesy lamps consist of the dome lamp, reading lamps, cargo lamps, and the left and right footwell lamps. Battery voltage is supplied to the courtesy lamps by the body control module (BCM) through an inadvertent power supply circuit. 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, the BCM will deactivate the inadvertent power supply to prevent a total battery discharge condition. Courtesy lamp operation is controlled by the BCM through low side drive control circuits, and any time the inadvertent power supply is active the BCM turns on the courtesy lamps by grounding the control circuits. The BCM will activate the courtesy lamps using inputs from the dome lamp switch on the headlamp switch assembly or any of the door jamb switches. The dome lamp switch signal is monitored from battery voltage by the BCM and when the switch is turned on the signal circuit will be closed to the headlamp switch low reference circuit.
Reference Information
Schematic Reference
Interior Lights Schematics Interior Lights Schematics
Connector End View Reference
Component Connector End Views Connector End Views By Name
Description and Operation
Interior Lighting Systems Description and Operation Interior Lighting Systems
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool Driver Door Ajar Sw. and Passenger Door Ajar Sw. parameters while opening and closing each vehicle door. The parameters should change between Door Ajar and Door Closed.
• If the parameter does not change between the selected states, refer to Door Ajar Indicator Malfunction Door Ajar Indicator Malfunction.
2. Observe the scan tool Courtesy Lamp Switch parameter while turning the courtesy lamp switch ON and OFF. The parameter should change between Active and Inactive.
• If the parameter does not change between the selected states, refer to Courtesy Lamp Switch Malfunction.
3. Command the Courtesy Lamps ON and OFF with a scan tool. The courtesy lamps should turn ON and OFF when changing between the commanded states.
• If the courtesy lamps do not turn ON and OFF when commanded, refer to Courtesy Lamp Malfunction.
Circuit/System Testing
Courtesy Lamp Switch Malfunction
1. Ignition OFF, disconnect the headlamp and panel dimmer switch.
2. Test for less than 5 ohm between the low reference circuit terminal 3 and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance.
3. Ignition ON, verify that the scan tool Courtesy Lamp Switch parameter displays Inactive.
• If not the specified value, test the signal circuit terminal 11 for a short to ground. If the circuit tests normal, replace the BCM.
4. Install a 3 A fused jumper wire between the signal circuit terminal 11 and the low reference circuit terminal 3. Verify the scan tool Courtesy Lamp Switch parameter displays Active.
• 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 the circuits test normal, replace the headlamp and panel dimmer switch.
Courtesy Lamp Malfunction
1. Ignition OFF, disconnect the harness connector at the dome/reading lamps.
2. Ignition ON, verify that a test lamp illuminates between the signal circuit terminal B 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 , test or replace the BCM.
3. Connect a test lamp between the control circuit terminal A and the signal circuit terminal B. Command the Courtesy Lamps 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 ground. If the circuit tests normal, replace the BCM.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
4. If all circuits test normal, test or replace the dome/reading lamps.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Headlamp Switch Replacement Service and Repair
* Dome Lamp Replacement Service and Repair
* Dome Lamp Bulb Replacement Service and Repair
* Control Module References Control Module References for BCM replacement, setup, and programming