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 System Diagnostic System Check?

Go to Step 2

Go to Symptoms - Lighting Systems

2

  1. Place the headlamp switch in the PARK position.
  2. Operate the Instrument Panel (I/P) dimmer switch.

Do the instrument panel lamps operate properly?

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

Go to Step 3

3

  1. Place the headlamp switch in the OFF position.
  2. Disconnect the I/P dimmer switch.
  3. Place the headlamp switch in the PARK position.

Are the instrument panel lamps illuminated?

Go to Step 4

Go to Step 6

4

  1. Place the headlamp switch in the OFF position.
  2. Disconnect the I/P dimming module.
  3. Place the headlamp switch in the PARK position.

Are the instrument panel lamps illuminated?

Go to Step 8

Go to Step 5

5

Test for a short to voltage in the instrument panel lamps dimmer switch signal circuit of the I/P dimmer switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

6

Inspect for poor connections at the harness connector of the I/P dimmer switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 9

7

Inspect for poor connections at the harness connector of the I/P dimming module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

8

Repair a short to voltage in the instrument panel lamps dimming control circuit of the I/P dimming module. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 11

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9

Replace the I/P dimmer switch. Refer to Instrument Panel Lamp Dimmer Switch Replacement .

Did you complete the replacement?

Go to Step 11

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10

Replace the I/P dimming module. Refer to Panel Dimming Module Replacement .

Did you complete the replacement?

Go to Step 11

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11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3