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

Connector End View Reference: Lighting Systems Connector End Views or Computer/Integrating Systems Connector End Views

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

1. Carefully supply sufficient light to the ambient light sensor.
2. Place the headlamps in the AUTO position.

Does the system operate normally?

Go to Testing for Electrical Intermittents

Go to Step 3

Remove the DRL fuse in the underhood fuse block.

Do the DRL turn OFF?

Go to Step 4

Go to Step 7

1. Reinstall the DRL fuse.
2. Use the scan tool to observe the DRL Status parameter while switching the headlamp switch back and forth several times between AUTO and HEAD.

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 underhood fuse block. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

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 .

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 .

Did you complete the repair?

Go to Step 10

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Replace the DRL relay. Refer to Relay Replacement .

Did you complete the replacement?

Go to Step 10

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Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 10

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3

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

Connector End View Reference: Lighting Systems Connector End Views , Computer/Integrating Systems Connector End Views in Computer/Integrating Systems, or Hydraulic Brake Connector End Views in Hydraulic Brakes

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

Verify that the daytime running lamps (DRL) are always on.

Do the DRL operate normally?

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

Go to Step 3

1. Apply the park brake.
2. Ensure that the headlamp switch is in the OFF position.
3. Install a scan tool.
4. Turn ON the ignition, with the engine OFF.
5. With the scan tool, observe the Park Brake Switch parameter in the body control module (BCM) data list.

Does the scan tool display Applied?

Go to Step 5

Go to Step 4

Test the signal circuit of the park brake switch for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct a condition?

Go to Step 16

Go to Step 8

With a scan tool, observe the Headlamp Off Switch data parameter in the BCM data list while cycling the headlamp switch between the DRL defeat and AUTO positions.

Does the scan tool change from Active to Inactive?

Go to Step 6

Go to Step 7

1. Carefully cover the ambient light sensor.
2. With the scan tool, observe the Ambient Light Sensor data parameter in the BCM data list.

Does the parameter indicate that there is sufficient light to activate the headlamps?

Go to Step 11

Go to Step 9

Test the headlamp switch headlamps off signal circuit and low reference circuit of the headlamp switch for an open, high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct a condition?

Go to Step 16

Go to Step 10

Inspect for poor connections at the harness connector of the park brake switch. Refer to Circuit Testing and Wiring 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 ambient light sensor. Refer to Circuit Testing and Wiring 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 harness connector of the headlamp and panel dimmer switch. 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

Inspect for poor connections at the harness connector of the BCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 15

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 ambient light sensor. Refer to Ambient Light Sensor Replacement .

Did you complete the replacement?

Go to Step 16

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Replace the headlamp and panel dimmer switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 16

--

Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 16

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1. Use the scan tool in order to clear any induced DTCs.
2. Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3