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 multifunction 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

Is only one headlamp inoperative?

Go to Step 4

Go to Step 6

4

Test the headlamp high or low beam supply voltage signal circuit for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 5

5

Test the inoperative lamp ground circuit for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 10

6

  1. Disconnect the multifunction switch.
  2. Connect a test lamp between the headlamp switch signal circuit of the multifunction switch and a good ground.

Does the test lamp illuminate?

Go to Step 11

Go to Step 7

7

  1. Disconnect the headlamp switch.
  2. Connect a test lamp between the battery positive voltage circuit of the headlamp switch and a good ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 12

8

Test the headlamp switch signal circuit for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 9

9

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 16

Go to Step 13

10

Inspect for poor connections at the harness connector of the inoperative lamp. 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 16

Go to Step 15

11

Inspect for poor connections at the harness connector of the multifunction 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 16

Go to Step 14

12

Repair the battery positive voltage circuit for an open. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 16

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13

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 16

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14

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

Did you complete the replacement?

Go to Step 16

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15

Replace the inoperative lamp. Refer to Headlamp Replacement or Headlamp Bulb Replacement .

Did you complete the replacement?

Go to Step 16

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16

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3