GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems in 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 dimmer switch to a low position.

Are the I/P lamps on?

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 headlamp switch.

Does the test lamp illuminate?

Go to Step 5

Go to Step 4

4

Repair a poor connection or an open in the park lamp switch ON circuit.

Did you complete the repair?

Go to Step 10

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5

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

Does the test lamp illuminate?

Go to Step 6

Go to Step 7

6

Replace the headlamp switch.

Refer to Headlamp Switch Replacement .

Did you complete the repair?

Go to Step 10

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7

Inspect the I/P dimmer switch control circuit for a poor connection, or an open.

Is the circuit OK?

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.

Did you complete the repair?

Go to Step 10

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9

Replace the LH I/P accessory wiring junction block.

Did you complete the repair?

Go to Step 10

--

10

Operate the system in order to verify the repair.

Did you correct the condition?

Go to Diagnostic System Check - Lighting Systems

Go to Step 2