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 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.
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.
Circuit/System Verification
1. Ignition ON, observe the scan tool Driver Door Open Sw. parameter while opening and closing the driver door. The reading should change between Open and Closed.
^ If the reading 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 reading does not change between Open and Closed, refer to Door Open Switch Circuit Test - Passenger.
3. Observe the scan tool Passenger Door Open Sw. parameter while opening and closing the left and right rear passenger doors. The reading should change between Open and Closed.
^ If the reading does not change between Open and Closed, refer to Door Open Switch Circuit Test - Passenger.
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 reading does not change between Off and Manual, refer to Dome Lamp Switch Circuit Test.
5. If all scan tool parameters test normal, refer to the appropriate circuit test listed below:
* Dome Lamp Circuit Test
* I/P Courtesy Lamp Circuit Test
* Inadvertent Power Courtesy Lamps Circuit Test
Circuit/System Testing
Door Open Switch Circuit Test - Driver
1. Ignition OFF, disconnect the harness connector at the driver door lock.
2. Verify that a test lamp illuminates between the appropriate ground circuit terminal listed below and B+.
* Base Level terminal 6
* Uplevel terminal 8
^ 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 appropriate signal circuit terminal listed below for a short to ground. If the circuit tests normal, replace the BCM.
* Base Level terminal 5
* Uplevel terminal 7
4. Install a 3A fused jumper wire between the appropriate signal circuit terminal listed and ground. Verify the scan tool Driver Door Open Sw. parameter is Open.
* Base Level terminal 5
* Uplevel terminal 7
^ 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 for Coupe) harness connector at the inoperative passenger door lock.
2. Verify that a test lamp illuminates between the appropriate ground circuit terminal listed below and B+.
* Front Passenger Door Lock terminal 3
* Left Rear Door Lock terminal 6
* Right Rear Door Lock terminal 3
^ 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 for a short to ground. If the circuit tests normal, replace the BCM.
4. Install a 3A fused jumper wire between the appropriate signal circuit terminal listed below and ground. Verify the scan tool Passenger Door Open Sw. parameter is Open.
* Front Passenger Door Lock terminal 2
* Left Rear Door Lock terminal 5
* Right Rear Door Lock terminal 2
^ 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 appropriate 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. If the circuit tests normal.
3. Ignition ON, verify the scan tool Ctsy. Lamp Actv. Reason parameter is OFF.
^ If not the specified value, test the signal circuit terminal 12 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 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. If all circuits test normal, test or replace the headlamp switch.
Dome Lamp Circuit Test
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.
I/P Courtesy Lamp Circuit Test
1. Ignition OFF, disconnect the harness connector at the I/P courtesy 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. Door Open, verify that a test lamp illuminates between the control circuit terminal A 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, replace the BCM.
4. If all circuits test normal, replace the inoperative I/P courtesy lamp.
Inadvertent Power Courtesy Lamps Circuit Test
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 inoperative 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 with 9C1 or 9C3
* 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 with 9C1 or 9C3
* 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 inoperative lamp.
Component Test
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.
* Base level driver door - signal terminal 5 and ground terminal 6
* Uplevel driver door - signal terminal 7 and ground terminal 8
* Front passenger - signal terminal 2 and ground terminal 3
* Left rear door - signal terminal 5 and ground terminal 6
* Right rear door - signal terminal 2 and ground terminal 3
^ If not the specified value, replace the appropriate 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.
* Base level driver door - signal terminal 5 and ground terminal 6
* Uplevel driver door - signal terminal 7 and ground terminal 8
* Front passenger - signal terminal 2 and ground terminal 3
* Left rear door - signal terminal 5 and ground terminal 6
* Right rear door - signal terminal 2 and ground terminal 3
^ If greater than the specified range, replace the appropriate door lock.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Headlamp Switch Replacement (Impala)
* Reading Lamp Bulb Replacement
* Instrument Panel Courtesy Lamp Bulb Replacement
* Sunshade Illuminated Mirror Lamp Bulb Replacement
* Dome Lamp Replacement (Impala)
* Dome Lamp Bulb Replacement (Impala)
* Emergency Vehicle Rear Compartment Lid Lamp Replacement (Impala RPO T53)
* Rear Compartment Lid Lamp Lens and Bulb Replacement (Impala RPO T53)
* Rear Compartment Courtesy Lamp Replacement
* Front Side Door Lock Replacement (Impala)
* Rear Door Lock Replacement
* Inside Rearview Mirror Replacement.