The BCM sounds the headlamps on reminder when one or more of the following conditions are present:

Was the BCM diagnostic system check performed?

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Go to Step 2

Go to Diagnostic System Check - Body Control System

1. Ensure that the IP dimmer switch is off.
2. Turn the ignition switch to RUN.
3. Lower the driver's window in order to prevent lockout.
4. Close the vehicle's doors.

Are the courtesy lights off?

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Go to Step 3

Go to Step 7

1. Connect a Scan Tool to the Data Link Connector (DLC).
2. Use the Scan Tool in order to monitor the park lamp off input.
3. While observing the Scan Tool , turn the headlamp switch from OFF to HEAD and back to OFF.

Does the Scan Tool indicate that the park lamp off input is active with the headlamp switch off?

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Go to Step 8

Go to Step 4

1. Turn the headlamp switch OFF.
2. Connect a test lamp.
3. Backprobe between the BCM connector C2 terminal D5 and ground.

Does the test lamp light?

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Go to Step 8

Go to Step 5

1. Disconnect the headlamp switch electrical connector.
2. Connect a test lamp.
3. Backprobe between the headlamp switch harness connector terminal E and ground.

Does the test lamp light?

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Go to Step 6

Go to Step 9

1. Disconnect the BCM connector C1.
2. Use a J 39200 digital multimeter (DMM) in order to measure the resistance between the BCM harness connector C1 terminal C2 and the headlamp switch harness connector terminal F.

Is the resistance measured less than the specified value?

2ohms

Go to Step 10

Go to Step 11

The headlamps on reminder is on with the driver's door closed due to a malfunction between the BCM and the driver's door lock ajar switch. Refer to Interior Lamps System Check in Lighting Systems for further diagnosis.

Is the action complete?

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Go to Step 12

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1. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.
2. Perform the Setup New BCM procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Is the repair complete?

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Go to Step 12

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1. Repair a poor connection in CKT 1340.
2. Repair an open in CKT 1340.

Is the repair complete?

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Go to Step 12

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1. Inspect the headlamp switch connection terminals E and F for a poor connection.
2. If the connection is OK, replace the headlamp switch assembly. Refer to Headlamp Switch Replacement in Lighting Systems.

Is the repair complete?

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Go to Step 12

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1. Repair a poor connection in CKT 1872.
2. Repair an open in CKT 1872.

Is the repair complete?

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Go to Step 12

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1. Turn the ignition switch to LOCK.
2. Reinstall the connectors and the components that were removed.
3. Check for BCM current DTCs. Refer to Diagnostic Trouble Code (DTC) Displaying in Body Control System.

Are there any BCM current DTCs present?

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Go to Diagnostic System Check - Body Control System in Body Control System

Go to Audible Warnings System Check