GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting System Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn the ignition to the ON position.
  2. Turn the headlamp switch to the ON position.
  3. Turn the I/P lamp dimmer switch to a high position.

Are the I/P lamps on?

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Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Disconnect the headlamp switch.
  2. Using a test lamp connected to a known good ground, probe the park lamp switch ON circuit at the I/P lamp dimmer switch.

Does the test lamp illuminate?

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Go to Step 5

Go to Step 4

4

Repair a poor connection or an open in the park lamp switch ON circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step 9

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5

Using a test lamp, probe the I/P lamp dimmer switch between the park lamp ON circuit and the I/P dimmer switch control circuit.

Does the test lamp illuminate?

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Go to Step 6

Go to Step 7

6

Replace the headlamp switch.

Refer to Headlamp Switch Replacement in Instrument Panel, Gauges, and Console.

Did you complete the repair?

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Go to Step 9

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7

Inspect the headlamp harness connect for a poor connection. Repair if necessary.

Did you complete the repair?

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Go to Step 9

Go to Step 8

8

Repair a poor connection, short to ground or an open in the I/P dimmer switch control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step 9

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9

Operate the system in order to verify the repair.

Did you correct the condition?

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Go to Diagnostic System Check - Lighting Systems

Go to Step 2