GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

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

1

Did you review the Exterior Lighting System Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Lighting Systems

2

  1. Turn OFF the ignition.
  2. Place the headlamp switch in the HEAD position.

Do the park lamp illuminate?

Go to Step 3

Go to Park Lamps Inoperative

3

  1. Place the headlamp switch in the OFF position.
  2. Verify the parking brake is disengaged.
  3. Cover the ambient light sensor.
  4. Turn ON the ignition, with the engine OFF.

Do the park lamp illuminate?

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

Go to Step 4

4

Are the automatic headlamps illuminated?

Go to Step 5

Go to Headlamps Inoperative in Low Light Conditions

5

  1. Turn OFF the ignition.
  2. Disconnect the daytime running lamps (DRL) control module.
  3. Turn ON the ignition, with the engine OFF.
  4. With a test lamp that is connected to ground, probe the battery positive voltage circuit of the DRL control module connector that is fed by the PARK LP Fuse.

Does the test lamp illuminate?

Go to Step 6

Go to Step 9

6

Connect a fused jumper between the battery positive voltage circuit and the park lamp supply voltage circuit of the daytime running lamps control module connector. Refer to Circuit Testing in Wiring Systems.

Do the park lamp illuminate?

Go to Step 7

Go to Step 8

7

Inspect for poor connections at the daytime running lamps (DRL) control module Refer to Testing for Intermittent Conditions and Poor Connections and to 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 park lamp supply voltage circuit of the DRL control module connector. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 11

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9

Repair an open or high resistance in the battery positive voltage circuit of the DRL control module connector that is fed by the PARK LP fuse. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 11

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10

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

Did you complete the replacement?

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 2