Daytime Running Lamps Malfunction

Daytime Running Lamps Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information





Circuit/System Description

The body control module (BCM) receives a signal from the ambient light/sunload sensor indicating a low or high ambient outside light level. Under daylight conditions the daytime running lamps are being supplied by battery voltage. The now closed relay supplies voltage to the day time running lamps. If the headlamps are illuminated the DRL will not illuminate.

Reference Information
Schematic Reference

Headlights/Daytime Running Lights (DRL) Schematics (Headlights/Daytime Running Lights (DRL) Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Exterior Lighting Systems Description and Operation (Exterior Lighting Systems Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Supply sufficient light to the ambient light sensor to simulate daylight conditions. With ignition ON, engine running, and the gear selector in drive, the daytime running lamps should illuminate.

Circuit/System Testing

DRL Malfunction
1. Supply sufficient light to the ambient light sensor to simulate daylight conditions.
2. Ignition ON, headlamp switch in the AUTOMATIC LIGHT position.
3. Observe the headlamps. The headlamps should not be illuminated.

• If the headlamps are illuminated, replace the B10 Ambient Light Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Headlamp Replacement (Headlamp Replacement)
* Control Module References (Programming and Relearning) for BCM replacement, setup and programming