GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Did you review the DRL circuit description and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Lighting Systems

2

  1. Clear the ambient light sensor of any obstructions.
  2. Start the engine.
  3. Observe the headlamps.

Did the headlamps illuminate at DRL intensity?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Engage the parking brake.

Did the brake indicator illuminate?

Go to Step 6

Go to Step 4

4

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

Did you find and correct the condition?

Go to Step 10

Go to Step 5

5

Test the ground circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 9

6

Did the charge indicator illuminate?

Go to Step 7

Go to Charge Indicator Always On

7

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

Did you find and correct the condition?

Go to Step 10

Go to Step 8

8

Test the DRL control circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 9

9

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

Did you complete the repair?

Go to Step 10

--

10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3