GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

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

1

Did you perform the Lighting Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Verify the fault is present.

Does the system operate normally?

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 3

3

  1. Set the park brake.
  2. Turn ON the ignition with the engine OFF.
  3. With the scan tool, read the park brake switch status.

Does the scan tool display SET?

Go to Step 4

Go to Step 5

4

With the scan tool, command the DRL relay OFF.

Do the DRL turn off?

Go to Step 7

Go to Daytime Running Lamps (DRL) Always On

5

  1. Disconnect the park brake switch.
  2. Connect a fused jumper wire between the park brake switch signal circuit of the park breke switch and a good ground.
  3. With the scan tool, read the park brake switch status.

Does the scan tool display SET?

Go to Step 8

Go to Step 6

6

Test the park brake 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 11

Go to Step 7

7

Inspect for poor connections at the harness connector of the BCM. 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 11

Go to Step 9

8

Inspect for poor connections at the harness connector of the park brake 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 11

Go to Step 10

9

Important: Perform the setup procedure for the BCM.

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 11

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10

Replace the park brake switch.

Is the replacement complete?

Go to Step 11

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11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3