GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Interior Lights Dimming Schematics

Connector End View Reference: Lighting Systems Connector End Views or Data Communication Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Verify that the interior backlighting does not dim.

Does the interior backlighting operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Test for a high resistance, an open, a short to ground, or a short to voltage in the following circuits. Refer to Circuit Testing and Wiring Repairs.

    • 5-volt reference
    • The dimming input
    • The dimming return

Did you find and correct a condition?

Go to Step 6

Go to Step 4

4

Inspect for poor connections at the harness connector of the headlamp switch. Refer to Circuit Testing and Wiring Repairs.

Did you find and correct the condition?

Go to Step 6

Go to Step 5

5

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 6

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6

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3