GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Fog Lights Schematics

Connector End View Reference: Lighting Systems Connector End Views or Computer/Integrating Systems Connector End Views in Computer/Integrating Systems

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Verify that the headlamps are inoperative in low light conditions.

Do the headlamps operate normally?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Turn the headlamp switch to the HEAD position.

Do the headlamps operate normally?

Go to Step 4

Go to Headlamps Inoperative - Low Beams

4

Use the Scan Tool to inspect for the following related Body Control Module (BCM) Data/ Input Parameters and Output Controls. Refer to Scan Tool Data List for typical values and definitions:

    • Headlamp ambient light sensor
    • Auto headlamps
    • Headlamp relay feedback
    • Daytime running lamps relay
    • Headlamp power relay
    • High beam switch
    • Flash-to-Pass switch

Did you find and correct a problem?

Go to Step 5

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5

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3