GM Service Manual Online
For 1990-2009 cars only

Step

Action

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No

Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics and Lighting Systems Connector End Views

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. Turn ON the ignition switch, with the engine OFF.
  2. Block the wheels.
  3. Disengage the parking brake.

Is the DRL indicator illuminated?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Are the DRLs illuminated?

Go to Step 4

Go to Daytime Running Lamps (DRL) Inoperative

4

Set the parking brake.

Does the brake warning indicator lamp illuminate?

Go to Step 5

Go to Brake Warning Indicator Inoperative

5

  1. Turn OFF the ignition.
  2. Release the parking brake.
  3. Disconnect the instrument panel cluster (IPC).
  4. Turn ON the ignition, with the engine OFF.
  5. Connect a test lamp between the DRL relay control circuit of the DRL indicator and the ignition 1 voltage circuit of the DRL indicator.

Does the test lamp illuminate?

Go to Step 7

Go to Step 6

6

Test the DRL relay control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 10

Go to Step 8

7

Inspect for poor connections at the harness connector of the IPC. Refer to Testing for Intermittent Conditions and Poor Connections .

Did you find and correct the condition?

Go to Step 10

Go to Step 9

8

Repair the following in the ignition 1 voltage circuit of the DRL indicator:

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

Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 10

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9

Replace the IPC. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

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 2