Buick Regal: Cornering Lamps Malfunction

Diagnostic Instructions

1. Cornering Lamps Malfunction

• 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.

Circuit/System Description

The cornering lamps are activated automatically at vehicle speeds below 40 km/h (25 MPH) when the turn signal/multifunction switch is placed in either the turn left or turn right positions and/or when the steering angle is changed from the straight-ahead position towards the side the vehicle is turning. When the headlamp control module detects that one of these operations has occurred, the headlamp control module sends a message via serial data to the left or right headlamp/cornering lamp control module. The appropriate headlamp/cornering lamp control module responds by applying battery voltage to the appropriate cornering lamp LED to illuminate the area that the vehicle is turning. The cornering lamps are deactivated automatically when the turn signal/multifunction switch is placed in the neutral position and/or the steering angle has returned in the straight-ahead position. The cornering lamps will not operate at vehicle speeds above 40 km/h (25 MPH).

Diagnostic Aids

When replacing a headlamp assembly, the following control modules located on each headlamp assembly are serviceable.

• K189L Headlamp/Cornering Lamp Control Module - Left
• K189R Headlamp/Cornering Lamp Control Module - Right
• K26L Headlamp Control Module - Left
• K26R Headlamp Control Module - Right

Reference Information

Schematic Reference

Headlights/Daytime Running Lights (DRL) Wiring Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Exterior 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. Ignition ON, low beam headlamps ON.

2. Verify the appropriate cornering lamp turns ON and OFF when commanding the appropriate Cornering Lamp ON and OFF with a scan tool.

• If the cornering lamp does not turn ON and OFF

3. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate E13 Headlamp Assembly.

4. Test for less than 15 Ω between the ground circuit terminal 1 and ground.

• 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

5. Ignition ON.

6. Verify a test lamp illuminates between the B+ circuit terminal 6 and ground.

• If the test lamp does not illuminate

1. Ignition OFF, disconnect the X5 harness connector at the X50A Fuse Block - Underhood.
2. Test for infinite resistance between the B+ 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 X50A Fuse Block - Underhood.

• Go to next step: If the test lamp illuminates

7. Test or replace the appropriate K189 Headlamp/Cornering Lamp Control Module.

8. Ignition ON.

9. Verify the cornering lamp turns ON and OFF when commanding the appropriate Cornering Lamp ON and OFF with a scan tool.

• If the cornering lamp does not turn ON and OFF

Replace the appropriate E13 Headlamp Assembly.

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

10. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Headlamp Replacement
• Headlamp LED Driver Module Replacement
• Control Module References for Headlamp/Cornering Lamp Control Module replacement, programming, and setup

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