Buick Regal: Sunshade Illumination Malfunction

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

1. Reading Lamps Always OFF
2. Sunshade Lamps Always OFF
3. Instrument Panel Compartment Lamp Always OFF

Circuit/System Description

The body control module (BCM) supplies the dome/reading lamps, sunshade and instrument panel compartment lamp with battery voltage. When switching on the following components the concerning lamps will illuminate:

• Dome/reading lamps
• Dome/reading lamps - row
• Sunshade - left Front
• Sunshade - right Front
• Instrument Panel compartment lamp

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 Verification

Ignition ON, observe the lamp of the sunshade - left front/sunshade - right front while opening and closing. The lamp should illuminate when opened.

Circuit/System Testing

Sunshade Light Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the appropriate sunshade.

2. Disconnect the negative terminal of the C1 Battery.

3. Test for less than 5 Ω between the ground circuit terminal B and ground.

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

4. Reconnect the negative terminal to the C1 Battery.

5. Ignition ON, test for greater than 11 V between the circuit terminal A and the ground circuit terminal B.

• If less than the specified range, test the 12 V circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

6. If all circuits test normal, test or replace the A3L Sunshade - Left or A3R Sunshade - Right.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Sunshade Replacement
• Sunshade Support Replacement
• Control Module References for BCM replacement, setup, and programming

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