Buick Regal: DTC B2652

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 B2652 02

Passenger Compartment Dimming 3 Circuit Short to Ground

Diagnostic Fault Information

1. Cigar Lighter Illumination at Full Intensity and Cannot be Dimmed or Turned OFF
2. Cigar Lighter Illumination do Not Illuminate

Circuit/System Description

The body control module (BCM) supplies a voltage reference to the backlight dimmer switch, which is part of the headlamp switch. When the backlight dimmer switch is placed in a desired position, reference voltage is applied through the backlight dimmer switch rheostat to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the instrument panel lamp control circuits illuminating the cigar lighter.

Conditions for Running the DTC

• The ignition is ON.
• The headlamps or park lamps are ON.

Conditions for Setting the DTC

The BCM detects a short to ground on the cigar lighter control circuit.

Action Taken When the DTC Sets

The BCM does not attempt to illuminate the cigar lighter.

Conditions for Clearing the DTC

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

Reference Information

Schematic Reference

Interior Lights Dimming 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

Circuit/System Verification

When opening the passenger door the Cigar Lighter illumination should go ON. When closing the driver door and locking the vehicle the Cigar Lighter illumination should go OFF after 5 s.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connectors at the E32 Cigarette Lighter Receptacle.

2. Test for less than 5 Ω between the ground circuit terminal C and ground.

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

3. Exterior lights OFF.

4. Ignition OFF.

5. Close all doors and lock the vehicle, test for less than 0.3 V between harness E32 Cigarette Lighter Receptacle terminal B and ground after 5 s.

• If greater than the specified value, test the circuit for a short to voltage. If the circuits test normal replace the K9 Body Control Module.

6. Unlock the vehicle.

7. Open the driver door.

8. Test for greater than 11 V between harness E32 Cigarette Lighter Receptacle terminal B and ground.

• If less than the specified value, test the circuit for a short to ground or an open/high resistance. If the circuits test normal replace the K9 Body Control Module.

9. If all circuits test normal, test or replace the E32 Cigarette Lighter Receptacle.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, programming and setup.

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