Operation CHARM: Car repair manuals for everyone.
Home >> Buick >> 2011 >> Regal L4-2.4L >> Repair and Diagnosis >> Lighting and Horns >> Testing and Inspection >> Courtesy Lamps Malfunction

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

Battery voltage for the courtesy lamps is supplied at all times to the body control module (BCM). When the BCM receives a signal to command the courtesy lamps ON, it then applies voltage through the dome/courtesy lamps control circuit to the courtesy lamps.

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 appropriate scan tool Door Ajar Switch parameter while opening and closing each vehicle door. The parameter should change between Active and Inactive.

• 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 Switch 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. All doors closed, observe the scan tool Dome Lamp Switch parameter while turning the dome lamp switch ON and OFF. The reading should change between Active and Inactive.

• If the Dome Lamp Switch parameter does not change between Active and Inactive, refer to Dome Lamp Switch Malfunction.

4. 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.

5. 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.

6. Turn the left and right sunshade lamps ON and OFF with their respective switches. The sunshade 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 Sunshade Illumination Malfunction.

7. 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 Rear Compartment Courtesy Lamp Malfunction.

8. Turn the instrument panel compartment lamp ON and OFF by turning the instrument panel compartment lamp switch ON and OFF. The instrument panel compartment lamp should turn ON and OFF when changing between the selected states.

• If the instrument panel compartment lamp does not turn ON and OFF when selected, refer to Instrument Panel Compartment Lamp Malfunction.

Circuit/System Testing

Dome Lamp Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the E37F dome/reading lamps - front.
2. Scan tool disconnected, doors CLOSED, interior lamps OFF, test for less than 5 ohm between the ground circuit terminal 6 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the scan tool Interior/Courtesy Lighting Master Switch parameter is Inactive.

• If not the specified value, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the K9 BCM.

4. Verify the scan tool Dome Lamp Switch parameter is Inactive.

• If not the specified value, test the signal circuit terminal 5 for a short to ground. If the circuit tests normal, replace the K9 BCM.

5. Connect a 3 A fused jumper wire between the signal circuit terminal 4 and ground. Verify the scan tool Interior/Courtesy Lighting Master Switch parameter is Active.

• If not the specified value, test the signal circuit for a short to B+ or an open/high resistance. If the circuit tests normal, replace the K9 BCM.

6. Connect a 3 A fused jumper wire between the signal circuit terminal 5 and ground. Verify the scan tool Dome Lamp Switch parameter is Active.

• If not the specified value, test the signal circuit for a short to B+ or an open/high resistance. If the circuit tests normal, replace the K9 BCM.

7. If all circuits test normal, replace the E37F dome/reading lamps - front.

Courtesy Lamp Malfunction
1. Disconnect the harness connector at the appropriate courtesy lamp.
2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5.0 ohm between the ground circuit terminal listed below and ground:

* E37 dome/reading lamp - terminal 6
* E1 accent lamp - terminal 2
* E8 instrument panel courtesy lamp - terminal 2

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal listed below and ground:

* E37 dome/reading lamp - terminal 2
* E1 accent lamp - terminal 1
* E8 instrument panel courtesy lamp - terminal 1

4. 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 OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.

5. If all circuits test normal, replace the courtesy lamp.

Reading Lamp Malfunction
1. Disconnect the harness connector at the appropriate E37 dome/reading lamp.
2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5.0 ohm between the ground circuit terminal 6 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between the control circuit terminal 1 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 K9 BCM.

4. If all circuits test normal, replace the E37 dome/reading lamp.

Sunshade Illumination Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate A3 sunshade.
2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5.0 ohm between the ground circuit terminal B and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, 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 K9 BCM.

4. If all circuits test normal, replace the A3 sunshade.

Rear Compartment Courtesy Lamp Malfunction
1. Ignition OFF, disconnect the harness connector at the E8S rear compartment courtesy lamp.
2. Open the trunk.
3. Verify that a test lamp illuminates between B+ and the ground circuit terminal 2.

• If the test lamp does not illuminate, test the ground circuit for short to voltage or an open/high resistance.

4. Ignition ON, verify that a test lamp illuminates between the control circuit terminal 1 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 K9 BCM.

5. If all circuits test normal, replace the E8S rear compartment courtesy lamp.

Instrument Panel Compartment Lamp Malfunction
1. Ignition OFF, disconnect the harness connector at the E27 instrument panel compartment lamp.
2. Open the instrument panel compartment.
3. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 2.

• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

4. Ignition ON, verify that a test lamp illuminates between the control circuit terminal 1 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 K9 BCM.

5. If all circuits test normal, replace the E27 instrument panel compartment lamp.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Refer to the appropriate replacement procedure for the lighting component that requires replacement.
* Control Module References (Programming and Relearning) for BCM replacement, programming and setup

pro multis · About Operation CHARM