GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Interior Lights Dimming Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

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

Go to Step 3

3

  1. Place the headlamp switch in the OFF position.
  2. Disconnect the I/P dimmer switch.
  3. Connect a 3-amp fused jumper wire between the I/P dimmer switch signal circuit and a good ground.
  4. Place the headlamp switch in the PARK position.

Does the back lighting illuminate?

Go to Step 4

Go to Step 5

4

Connect the fused jumper wire between the I/P dimmer switch signal circuit and the I/P dimmer switch ground circuit.

Does the back lighting illuminate?

Go to Step 7

Go to Step 6

5

Test the I/P dimmer switch signal circuit for an open, high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 8

6

Test the I/P dimmer switch ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 8

7

Inspect for poor connections at the I/P dimmer switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 9

8

Inspect for poor connections at the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 10

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 BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the repair?

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