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 System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Expose the ambient light sensor to a bright incandescent lamp.
  2. Turn ON the ignition, with the engine OFF.
  3. Place the headlamp switch in the OFF position.
  4. Ensure the parking brake is disengaged.

Do the daytime running lamps (DRL) illuminate?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Disconnect the DRL resistor.
  2. Connect a 15-amp fused jumper wire between the ground circuit of the DRL relay at the DRL resistor connector and a good ground.

Are the headlamps illuminated?

Go to Step 4

Go to Step 5

4

Connect a 15-amp fused jumper wire between the ground circuit of the DRL relay at the DRL resistor connector and the ground circuit at the DRL resistor connector.

Are the headlamps illuminated?

Go to Step 7

Go to Step 8

5

Test the ground circuit of the DRL relay for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 6

6

Inspect for poor connections at the DRL relay. 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

7

Inspect for poor connections at the harness connector of the DRL resistor. 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

8

Repair an open or high resistance in the ground circuit of the DRL resistor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 11

--

9

Replace the DRL relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 11

--

10

Replace the DRL resistor.

Did you complete the replacement?

Go to Step 11

--

11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2