GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Headlights Schematics

1

Did you perform the Lighting Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Verify the fault is present.

Does the system operate normally?

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 3

3

  1. Turn ON the headlamp switch.
  2. Disconnect the headlamp dimmer switch connector C201C.

Are both the high and the low beam off?

Go to Step 4

Go to Step 6

4

Connect a test lamp from between the headlamp dimmer switch output-low circuit and a good ground, then between the headlamp dimmer switch output-high circuit and to a good ground at connector C201C.

Does the test lamp illuminate at both terminals?

Go to Step 7

Go to Step 5

5

Repair the open in the headlamp dimmer switch output-low circuit or the headlamp dimmer switch output-high circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 8

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6

Repair the short to ground in the headlamp dimmer switch output-low circuit or in the headlamp dimmer switch output-high circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 8

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7

Replace the headlamp dimmer switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column - Tilt.

Did you complete the repair?

Go to Step 8

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8

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3