Buick Regal: DTC B2615

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.

DTC Descriptor

DTC B2615 02

Passenger Compartment Dimming 2 Circuit Short to Ground

Diagnostic Fault Information

1. Dome Lamps Malfunction

Circuit/System Description

The dome lamp switch has 3 positions: DOOR, OFF, and ON. The ON position provides a ground for continuous operation and the dome lamp will remain illuminated until the switch is placed in either the DOOR or OFF position. When in the DOOR position, the dome lamp operation is controlled by the body control module (BCM). When any door is opened, the door ajar switch contacts close and the BCM receives a door-open input. The BCM illuminates the dome lamp when any door is opened or a door lock/unlock request is activated with the key fob. After all doors have been closed, the dome lamp will remain illuminated approximately 3 seconds after the last door closes. When the driver places the dome lamp switch in the OFF position, the dome lamp will be disabled. In the event that the dome lamp were to remain illuminated for more than 10 minutes with the ignition switch in the OFF position and no doors opened, the BCM will deactivate the dome lamp control circuit to prevent total battery discharge.

Conditions for Running the DTC

Battery voltage must be between 9-16 V.

Conditions for Setting the DTC

DTC B2615 02

• The BCM detects a short to ground in the dome lamps control circuit terminal 1 X7.
• The BCM detects a short to ground or an open/high resistance in the F5 DA fuse B+ circuit.

Actions Taken When the DTC Sets

The BCM will disable the dome lamps control circuit terminal 1 X7 or terminal 5 X2.

Conditions for Clearing the DTC

• The condition responsible for setting the DTC no longer exists.
• A history DTC will clear once 100 consecutive malfunction - free ignition cycles have occurred.

Reference Information

Schematic Reference

Interior Lights Wiring Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

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 Testing

NOTE: Each lighting component may need to be disconnected to isolate a short to ground. Use the schematics to identify the following:

• Lighting components the vehicle is equipped with
• Each component's control and ground circuit terminals
• Component locations on the lighting control circuit

1. Ignition OFF, all doors closed, all accessories OFF, open and close drivers door, disconnect the harness connector at the appropriate component listed below. It may take up to 2 min for all vehicle systems to power down.

• A98 Front Overhead Console Assembly
• E37R Dome/Reading Lamps - Rear
• E1AA Floor Accent Lamp - Left Front
• E1AB Floor Accent Lamp - Right Front

2. Test for less than 15 Ω between the appropriate ground circuit terminal listed below and ground.

• A98 Front Overhead Console Assembly terminal 5
• E37R Dome/Reading Lamps - Rear terminal 3
• E1AA Floor Accent Lamp - Left Front terminal 2
• E1AB Floor Accent Lamp - Right terminal 2
• If 15 Ω or greater

1. Ignition OFF.
2. Test for less than 2 Ω in the ground circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, repair the open/high resistance in the ground connection.

• Go to next step: If less than 15 Ω

3. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON.

• A98 Front Overhead Console Assembly terminal 8
• E37R Dome/Reading Lamps - Rear terminal 2
• E1AA Floor Accent Lamp - Left Front terminal 1
• E1AB Floor Accent Lamp - Right terminal 1

4. Verify the test lamp turns ON and OFF when commanding the Courtesy Lamps ON and OFF with a scan tool.

• If the test lamp is always OFF

1. Ignition OFF, disconnect the X7 harness connector listed below at the K9 Body Control Module.
2. Test for infinite resistance between the control circuit and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • Go to next step: If infinite resistance
3. Test for less than 2 Ω in the control circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K9 Body Control Module.

• If the test lamp is always ON

1. Ignition OFF, disconnect the X7 harness connector listed below at the K9 Body Control Module.
2. Test for less than 1 V between the control circuit terminal and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • If less than 1 V, replace the K9 Body Control Module.

• Go to next step: If the test lamp turns ON and OFF

5. Test or replace the appropriate dome/floor accent lamp.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Center Reading Lamp Replacement (without Sunroof)
• Rear Seat Position Center Reading Lamp Replacement (with Sunroof)
• Front Floor Flood Lamp Replacement
• Control Module References for BCM replacement, programming, and setup

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