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

Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System

Did you perform the Lighting Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

1. Ensure the park brake is released.
2. Supply sufficient light to the ambient light sensor to simulate daytime conditions.
3. Turn ON the ignition, with the engine OFF.
4. With the brake pedal depressed, place the gear selector in any drive gear.
5. Place the headlamps in the AUTO position.

Does the system operate normally?

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 3

Disconnect the affected daytime running lamp (DRL) relays.

Do the DRL turn OFF?

Go to Step 4

Go to Step 7

1. Reconnect the DRL relays.
2. Use the scan tool to observe the DRL parameter and command the DRL ON and OFF several times.

Does the DRL parameter change states as expected?

Go to Step 5

Go to Step 6

Inspect for poor connections at the harness connector of the affected 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 10

Go to Step 8

Inspect for poor connections at the harness connector of the body control module (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 10

Go to Step 9

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

Did you complete the repair?

Go to Step 10

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

Did you complete the replacement?

Go to Step 10

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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 10

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3