GM Service Manual Online
For 1990-2009 cars only

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

Connector End View Reference: Master Electrical Component List in Wiring Systems

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

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.
  5. Block the wheels.
  6. Place the transaxle in neutral.

Do the daytime running lamps (DRL) illuminate?

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

Go to Step 3

3

  1. Disconnect the DRL relay.
  2. Connect a 15-amp fused jumper wire between the headlamp low beam signal circuit of the DRL relay and the DRL resistor supply voltage circuit of the DRL relay.

Do the DRL illuminate?

Go to Step 6

Go to Step 4

4

  1. Leave the fused jumper wire connected.
  2. Disconnect the DRL resistor.
  3. Connect a 15-amp fused jumper wire between the DRL resistor supply voltage circuit of the DRL resistor and a good ground.

Do the headlamps illuminate?

Go to Step 5

Go to Step 8

5

Test the ground circuit of the DRL resistor 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 7

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 DRL resistor supply voltage circuit. 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