GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

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

Place the headlamps in the ON position.

Does the system operate normally?

Go to Step 3

Go to Step 4

3

  1. Turn the headlamp switch to the AUTO position.
  2. Cover the ambient light sensor in order to block out all light.

Do the headlights illuminate and the daylight running lamps (DRL) turn off?

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 4

4

  1. Turn OFF the ignition .
  2. Disconnect the body control module (BCM) C1.
  3. Turn ON the ignition, with the engine OFF.

Do the DRL turn OFF?

Go to Step 8

Go to Step 5

5

Disconnect the DRL relay.

Do the DRL turn OFF?

Go to Step 6

Go to Step 9

6

Test the DRL relay control circuit of the BCM for a short to ground.

Did you find and correct the concern?

Go to Step 12

Go to Step 7

7

Inspect for poor connections at the harness connector of 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 12

Go to Step 10

8

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 12

Go to Step 11

9

Repair the DRL supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 12

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10

Replace the DRL relay. Refer to Daytime Running Lamps (DRL) Relay Replacement .

Did you complete the replacement?

Go to Step 12

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11

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 12

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12

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3