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 Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Verify the fault is present.

Did the system operate normally?

Go to Testing for Electrical Intermittents

Go to Step 3

3

Turn the park lamps ON.

Do the park lamps function properly?

Go to Step 4

Go to Park Lamps Inoperative

4

Disconnect the headlamp and panel dimmer switch.

Are the instrument panel lamps illuminated?

Go to Step 6

Go to Step 5

5

Remove the ILLUM fuse. Refer to Testing for a Short to Voltage in Wiring Systems.

Are the instrument panel lamps illuminated?

Go to Step 7

Go to Step 8

6

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

Did you complete the repair?

Go to Step 9

--

7

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

Did you complete the repair?

Go to Step 9

--

8

Replace the headlamp and panel dimmer switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 9

--

9

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3