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. Block the drive wheels.
2. Turn the ignition ON, with the engine OFF.
3. Place the gear selector in the DRIVE position.
4. Ensure the headlamp switch is in the AUTO position.
5. Ensure the ambient light sensor is not covered or has no obstruction to daylight.

Does the system operate normally?

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 3

Is only one daytime running lamp (DRL) inoperative?

Go to Step 4

Go to Step 5

Test the DRL supply voltage circuit of the affected lamp 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 16

Go to Step 14

1. Ensure the park brake is not set.
2. Install a scan tool.
3. Turn ON the ignition, with the engine OFF.
4. With the scan tool, observe the park brake switch parameter in the Body Control Module (BCM) Data List.

Does the scan tool display RELEASED?

Go to Step 7

Go to Step 6

Test the signal circuit of the park brake switch for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 10

1. Turn OFF the ignition.
2. Remove the DRL relays.
3. Connect a 3-amp fused jumper wire between the DRL diode supply voltage and the DRL supply voltage circuits of the DRL relays.

Do the DRL illuminate?

Go to Step 9

Go to Step 8

Test for an open or high resistance in the DRL diode supply voltage circuit.

Did you find and correct the condition?

Go to Step 16

Go to Step 11

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 16

Go to Step 12

Inspect for poor connections at the harness connector of the park brake switch. 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 16

Go to Step 13

Inspect for poor connections at the DRL Diode. 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 16

Go to Step 15

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 16

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Replace the park brake switch. Refer to Parking Brake Indicator Switch Replacement in Park Brake.

Did you complete the replacement?

Go to Step 16

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

Did you complete the replacement?

Go to Step 16

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Replace the DRL Diode. Refer to Daytime Running Lamp (DRL) Diode Replacement .

Did you correct the condition?

Go to Step 16

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3