GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Place the headlamp switch in the HEADLAMP position.
  2. Place the headlamp dimmer switch in the HIGH position.
  3. Place the headlamp dimmer switch in the LOW position.

Do the headlamps illuminate in both headlamp dimmer switch positions?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Do the headlamps illuminate in only the HIGH or LOW headlamp dimmer switch positions?

Go to Headlamps Inoperative - High Beams or Headlamps Inoperative - Low Beams

Go to Step 4

4

  1. Place the headlamp switch in the OFF position.
  2. Disconnect the turn signal/multifunction switch.
  3. Place the headlamp switch in the HEADLAMP position.
  4. Probe the headlamp switch signal circuit at the turn signal/multifunction switch with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 7

Go to Step 5

5

  1. Place the headlamp switch in the OFF position.
  2. Disconnect the headlamp switch.
  3. Probe the battery positive voltage circuit of the headlamp switch with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 9

6

Test the headlamp switch signal circuit for the following:

    • An open
    • A high resistance
    • A short to ground

Refer to Circuit Testing and Wiring Repairs.

Did you find and correct the condition?

Go to Step 12

Go to Step 8

7

Inspect for poor connections at the harness connector of the turn signal/multifunction switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 12

Go to Step 10

8

Inspect for poor connections at the harness connector of the headlamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 12

Go to Step 11

9

Repair the following in the battery positive voltage circuit of the headlamp switch:

    • An open
    • A high resistance
    • A short to ground

Refer to Circuit Testing and Wiring Repairs.

Did you complete the repair?

Go to Step 12

--

10

Replace the turn signal/multifunction switch. Refer to Turn Signal Multifunction Switch Replacement.

Did you complete the replacement?

Go to Step 12

--

11

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 12

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12

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2