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 body control module (BCM) applies battery voltage to the courtesy lamps through the courtesy lamps control circuit. When any door is opened, the door ajar switch contacts close and the BCM receives a door-open input. If the BCM receives a door lock or unlock input or a rear hatch open input, the BCM will activate the courtesy lamps control circuit, providing battery voltage to all of the dome lamps and reading lamps. The dome lamps are provided with battery voltage via the courtesy lamps control circuit and ground through the courtesy lamps low control circuit. In the event that any of these lamps were to remain illuminated for more than 20 minutes with the ignition switch in the OFF position, the BCM will deactivate the courtesy lamp high control circuit to prevent a total battery discharge condition.
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 (Programming and Relearning)for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool Door Ajar Switch parameter while opening and closing each vehicle door. The parameter 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 Liftgate Ajar Switch parameter while opening and closing the liftgate. The parameter should change between Ajar and Closed.
• If the parameter does not change between the selected states, refer to Liftgate Ajar Indicator Malfunction (Liftgate Ajar Indicator Malfunction).
3. Command the Interior 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.
4. Turn the individual reading lamps ON and OFF with their respective switches. The reading lamps should turn ON and OFF when changing between the selected states.
• If any reading lamp does not turn ON and OFF when selected, refer to Reading Lamp Malfunction.
Circuit/System Testing
Courtesy Lamp Malfunction
Note: Each courtesy lighting component may need to be disconnected to isolate a short to voltage or short to ground. Use the schematic to identify the following:
* Courtesy lighting components the vehicle is equipped with.
* Component locations on the interior lighting schematic
* Each component's control and ground circuit terminals
1. Ignition OFF, disconnect the harness connector at any component with inoperative courtesy lighting.
2. Ignition ON, verify that a test lamp illuminates between the B+ 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.
3. Connect a test lamp between the B+ circuit terminal B and the control circuit terminal listed below:
* Dome/reading lamps - rear - terminal A
* Dome/reading lamps - front (with CF5) - terminal C
* Dome/reading lamps - front (without CF5) - terminal A
* Dome lamp - terminal A
4. Command the Interior 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.
5. If all circuits test normal, test or replace the courtesy light.
Reading Lamp Malfunction
Note: Each reading light component may need to be disconnected to isolate a short to voltage or short to ground. Use the schematic to identify the following:
* Reading light components the vehicle is equipped with.
* Component locations on the interior lighting schematic
* Each component's control and ground circuit terminals
1. Ignition OFF, disconnect the harness connector at any component with inoperative reading lighting.
2. Ignition ON, verify that a test lamp illuminates between B+ and the ground circuit terminal listed below:
* Dome/reading lamps - rear - terminal C
* Dome/reading lamps - front (with CF5) - terminal A
* Dome/reading lamps - front (without CF5) - terminal C
• If the test lamp does not illuminate, test the ground circuit for a short to voltage or an open/high resistance.
3. Connect a test lamp between the B+ circuit terminal B and the control circuit terminal.
4. Turn the reading light ON and OFF with the appropriate switch. The test lamp should turn ON and OFF when changing between the selected 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.
5. If all circuits test normal, test or replace the reading light.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Refer to the appropriate replacement procedure for the component causing the condition.
* Control Module References (Programming and Relearning)for BCM replacement, setup, and programming