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 IP dimmer 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 2 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 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, Gauges, and Console.

Did you complete the repair?

Go to Step 10

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9

Replace the IP dimmer switch. Refer to Instrument Panel Lamp Dimmer 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