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 INT LIGHTS fuse supplies battery voltage to the body control module (BCM). The BCM applies battery 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. For more detailed information concerning courtesy lamp operation refer to Interior Lighting Systems Description and Operation (Interior Lighting Systems).
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.
* Dome/Reading Lamp
* Vanity Mirror Lamps
* Reading Lamp Assembly
* Inside Rearview Mirror
* Rear Compartment Courtesy Lamp
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.
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 Rear Closure Ajar Sw. parameter while opening and closing the trunk. The parameter should change between Active and Inactive.
• If the parameter does not change between the selected states, refer to Trunk Ajar Indicator Malfunction (Trunk Ajar Indicator 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 Dome 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 Inadvertent Power Courtesy Lamps Malfunction.
5. Turn the left and right vanity mirror lamps ON and OFF with their respective switches. The vanity mirror 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 Inadvertent Power Courtesy Lamps Malfunction.
6. Turn the rear compartment courtesy lamp ON and OFF by opening and closing the trunk. The rear compartment courtesy lamp should turn ON and OFF when changing between the selected states.
• If the rear compartment courtesy lamp does not turn ON and OFF when selected, refer to Inadvertent Power Courtesy Lamps Malfunction.
Circuit/System Testing
Dome Lamp Malfunction
1. Ignition OFF, disconnect the harness connector at the 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.
Inadvertent Power Courtesy Lamps Malfunction
1. Ignition OFF, disconnect the X3 harness connector at the BCM.
2. Ignition ON, 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.
3. Ignition OFF, connect the X3 harness connector at the BCM and disconnect the harness connector at the appropriate courtesy lamp.
4. Verify that a test lamp illuminates between the appropriate ground circuit terminal listed below and B+.
* Dome/Reading Lamp - terminal B
* Left or Right Vanity Mirror - terminal B
* Reading Lamp Assembly - terminal B
* Inside Rearview Mirror - terminal 7 (w/O UE1)
* Inside Rearview Mirror - terminal 8 (with UE1)
* Rear Compartment Courtesy Lamp - terminal B
• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
5. Ignition ON, verify that a test lamp illuminates between the appropriate inadvertent power courtesy lamp circuit terminal listed below and ground.
* Dome/Reading Lamp - terminal B
* Left or Right Vanity Mirror - terminal B
* Reading Lamp Assembly - terminal A
* Inside Rearview Mirror - terminal 2 (w/O UE1)
* Inside Rearview Mirror - terminal 6 (with UE1)
* Rear Compartment Courtesy Lamp - terminal A
• 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, replace the BCM.
6. If all circuits test normal, test or replace the courtesy lamp.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Headlamp Switch Replacement (Impala) (Service and Repair)
* Reading Lamp Bulb Replacement (Service and Repair)
* Instrument Panel Courtesy Lamp Bulb Replacement (Instrument Panel Courtesy Lamp Bulb Replacement)
* Sunshade Illuminated Mirror Lamp Bulb Replacement (Sunshade Illuminated Mirror Lamp Bulb Replacement)
* Dome Lamp Replacement (Impala) (Service and Repair)
* Dome Lamp Bulb Replacement (Impala) (Service and Repair)
* Emergency Vehicle Rear Compartment Lid Lamp Replacement (Impala RPO T53) (Emergency Vehicle Rear Compartment Lid Lamp Replacement (RPO T53))
* Rear Compartment Lid Lamp Lens and Bulb Replacement (Impala RPO T53) (Rear Compartment Lid Lamp Lens and Bulb Replacement (RPO T53))
* Rear Compartment Courtesy Lamp Replacement (Rear Compartment Courtesy Lamp Replacement)
* Front Side Door Lock Replacement (Front Side Door Lock Replacement)
* Rear Side Door Lock Replacement (Rear Side Door Lock Replacement)
* Inside Rearview Mirror Replacement (Inside Rearview Mirror Replacement)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming