GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • 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

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Dome/Courtesy Lamp Control

B2615 02

B2615 04

B2615 01

--

Dome Lamp Defeat Signal

2, 3

3

3

--

Dome Lamp Switch ON Signal

1, 4

4

4

--

Dome Lamp Ground

--

2

--

--

1. Dome/Courtesy lamps always illuminated

2. Dome/Courtesy lamps do not illuminate

3. Dome lamps Defeat switch inoperative

4. Dome lamps On switch inoperative

Circuit/System Description

The dome lamp which is located on the dome/reading lamps module and accent lamps are controlled by the body control module (BCM). Inputs from the dome lamp switch and the door ajar switches are monitored by the BCM. When a door ajar switch is closed, or the dome lamp switch is turned to the ON position, the BCM supplies the B+ for the dome and courtesy lamps.

Reference Information

Schematic Reference

Interior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Interior Lighting Systems Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Observe the driver information center while opening and closing each vehicle door and the liftgate. The driver information center should display the door ajar/liftgate ajar message only when the door/liftgate is open.
  2. If the driver information center displays the door ajar/liftgate ajar message when a door or the liftgate is closed, refer to Door Ajar Indicator Malfunction.
  3. Ignition ON, Dome/Reading Lamps switch in the DEFEAT position, observing the scan tool Dome Lamp Switch parameter. The parameter should change between Defeat, On and Auto.
  4. If the parameter is always Auto or Defeat, refer to Dome Lamp Defeat Switch Malfunction.
    If the parameter is always Auto or On, refer to Dome Lamp ON Switch Malfunction.
  5. Ignition OFF, open driver door, the dome and accent lamps should go ON.
  6. If the dome and courtesy lamps stay OFF, refer to Dome Lamp Malfunction.

Circuit/System Testing

Dome Lamp DEFEAT Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the E37A Dome/Reading Lamps.
  2. Test for less than 5 Ω between the ground circuit terminal 6 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify the scan tool Dome Lamp Switch parameter is OFF.
  5. If not the specified state, test the dome defeat signal circuit terminal 4 for short circuit to ground. If the circuit tests normal, replace the K9 Body Control Module (BCM).
  6. Install a 3 A fused jumper wire between the dome defeat signal circuit terminal 4 and the ground circuit terminal 6. Verify the scan tool Dome Lamp Switch parameter is Defeat.
  7. If not the specified state, test the dome defeat signal circuit for short circuit to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module (BCM).
  8. If all circuits test normal, test or replace the E37A Dome/Reading Lamps.

Dome Lamp ON Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the E37A Dome/Reading Lamps.
  2. Test for less than 5 Ω between the ground circuit terminal 6 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, test for greater than 11 V between the 12 V reference circuit terminal 1 and ground.
  5. If not the specified state, test the dome on signal circuit terminal 5 for short circuit to ground. If the circuit tests normal, replace the K9 Body Control Module (BCM).
  6. If all circuits test normal, test or replace the E37A Dome/Reading Lamps.

Dome Lamp Malfunction

  1. Ignition OFF, disconnect the harness connectors at the E37A Dome/Reading Lamps.
  2. Test for less than 5 Ω between the ground circuit terminal 6 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Connect a test lamp between the control circuit terminal 2 and the ground circuit terminal 6.
  5. Command the Courtesy Lamps ON and OFF with the scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
  6. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module (BCM).
    If the test lamp is always OFF, test the control circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the K9 Body Control Module (BCM).
  7. If all circuits test normal, test or replace the E37A Dome/Reading Lamps.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Dome Lamp Replacement
    •  Dome Lamp Bulb Replacement
    •  Control Module References for BCM replacement, setup, and programming