GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you review the Exterior Lighting Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Exterior Lighting Systems Description and Operation

2

  1. Clear the ambient light sensor of any obstructions.
  2. Start the engine.
  3. Turn headlamp switch to HEAD and observe the headlamps.

Did the headlamps illuminate from DRL to full intensity?

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

Go to Step 3

3

Cover the ambient light sensor for 1 minute.

Did the headlamps illuminate at full intensity?

Go to Step 6

Go to Step 4

4

  1. Disconnect the DRL control module connector.
  2. Test the headlamp signal circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 7

Go to Step 5

5

Replace the DRL control module. Refer to Daytime Running Lights (DRL) Control Module Replacement .

Did you complete the repair?

Go to Step 7

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6

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the repair?

Go to Step 7

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7

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3