GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

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

Connector End View Reference: Lighting Systems Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Verify that the low beam headlamps are inoperative.

Do the headlamps operate normally?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Move the headlamp switch to the HEAD position.
  2. Move the headlamp dimmer switch to the LOW BEAM position.

Is only one headlamp inoperative?

Go to Step 4

Go to Step 5

4

Test for the following conditions. Refer to Circuit Testing in Wiring Systems.

    • An open, high resistance or short to ground in the inoperative low beam headlamp supply voltage circuit
    • An open or high resistance in the inoperative headlamp dimmer switch low beam signal circuit

Was a problem found?

Go to Step 7

Go to Step 8

5

Backprobe the headlamp dimmer switch low beam signal circuit at connector C 201 using a test lamp from ground. Refer to Circuit Testing in Wiring Systems.

Does the test lamp illuminate?

Go to Step 9

Go to Step 6

6

Repair the open or high resistance in the headlamp dimmer switch low beam signal circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 10

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7

Repair one of the following conditions. Refer to Wiring Repairs in Wiring Systems.

    • An open, high resistance or short to ground in the inoperative low beam headlamp supply voltage circuit
    • An open or high resistance in the headlamp dimmer switch low beam signal circuit

Did you complete the repair?

Go to Step 10

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8

Replace the inoperative headlamp bulb. Refer to Sealed Beam Headlamp Replacement or Headlamp Replacement .

Did you complete the repair?

Go to Step 10

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9

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

Did you complete the repair?

Go to Step 10

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10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3