GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Headlights Schematics

1

Did you review the headlamp operation and perform the necessary inspections?

Go to Step 2

Go to Exterior Lighting Systems Description and Operation

2

  1. Turn ON the headlamps.
  2. Turn the dimmer switch to the low beam position and then to the high beam position.

Does the headlamp system operate normally?

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 3

3

Disconnect the headlamp switch connector.

Are the headlamps still illuminated?

Go to Step 4

Go to Step 7

4

Test the headlamp switch signal circuit between the dimmer switch and the headlamp switch for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 5

5

Disconnect the dimmer switch connector.

Are the headlamps still illuminated?

Go to Step 8

Go to Step 6

6

Inspect for poor connections at the harness connector of the 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 headlamp 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 10

8

Repair the headlamp high beam supply voltage or headlamp low beam supply voltage circuit for a short to voltage. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 11

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9

Replace the dimmer switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 11

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10

Replace the headlamp switch. Refer to Headlamp Switch 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