Battery positive voltage is applied to the headlamp control module at all times. The headlamp control module has a normal operational voltage range of about 12.5-16 volts and is only fully functional with the ignition switch is in the RUN position and the headlamp switch in the AUTO position. The communications enable signal from the BCM wakes the headlamp control module microprocessor. The headlamp control module receives serial data messages from the engine control module (ECM), transmission control module (TCM), electronic brake control module (EBCM), and body control module (BCM) with regards to power mode, speed, steering angle, transmission gear selection, and headlamp switch status. The headlamp control module calculates the headlamp angle and sends commands to the left and right adaptive forward lighting system (AFL) headlamp actuators. The headlamp actuators drive the headlamps to the position commanded by the headlamp control module. The headlamp control module monitors the headlamp actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory and the driver will be notified with a message displayed over the driver information center (DIC) located on the instrument panel cluster (IPC).

Diagnose any faults to the vehicle stability enhancement system (VSES) which contains the steering wheel position sensor before proceeding with this diagnostic procedure. A fault within the steering wheel position sensor will cause the adaptive forward lighting system to be inoperative.

Schematic Reference

Headlights/Daytime Running Lights (DRL) Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, with a scan tool, command the AFL Motor Control Left and Right while observing both headlamps. Both headlamps should operate to the Left and Right positions when commanded.

1. Ignition OFF, disconnect the harness connector at the inoperative headlamp.
2. Remove the AFS 15A fuse.
3. Ignition OFF, scan tool OFF, test for 10 ohms -25K ohms between each control circuit terminal listed below and ground.

•	AFL motor control terminal 1

•	AFL motor control terminal 2

•	AFL motor control terminal 3

•	AFL motor control terminal 4

⇒	If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the headlamp control module.

⇒	If less than the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the headlamp control module.

4. Install the AFS 15A fuse.
5. Ignition ON, scan tool OFF, headlamps ON, verify that a test lamp does not illuminate between each control circuit terminal listed below and ground.

•	AFL motor control terminal 1

•	AFL motor control terminal 2

•	AFL motor control terminal 3

•	AFL motor control terminal 4

⇒	If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp control module.

6. If all circuits test normal, replace the appropriate headlamp assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.