GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Interior Lights Dimming Schematics

1

Did you perform the Lighting Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Verify that the interior backlighting does not dim.

Does the interior backlighting operate normally?

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

Go to Step 3

3

Are the instrument cluster backlighting lamps the only lamps that do not dim?

Go to Step 8

Go to Step 4

4

Remove the ILLUM fuse in the IP Fuse Block.

Do the affected lamps remain on?

Go to Step 6

Go to Step 5

5

Reinstall the fuse and remove the headlamp switch.

Do the affected lamps remain on?

Go to Step 7

Go to Step 9

6

Repair the short to voltage in the instrument panel lamp fuse supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 10

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7

Repair the short to ignition voltage in the instrument panel lamps dimmer switch signal circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 10

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8

Replace the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.

Did you complete the repair?

Go to Step 10

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9

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the repair?

Go to Step 10

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10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3