Headlamp Alignment Actuator - Operation

OPERATION

The controller board and logic circuitry of the headlamp leveling and swiveling motors control motor operation based upon electronic message inputs received from the Adaptive Front Lighting System (AFLS) module over the Local Interface Network (LIN) data bus. The AFLS module is a LIN master node, while each of the leveling and swiveling motors is a LIN slave node. The AFLS module sends commands to the stepper motors based upon many external hard wired and electronic message inputs. The microprocessor in each stepper motor drives the motor and monitors the positioning of the lamp.

The headlamp leveling and swiveling motors have a path to ground at all times. The AFLS module and the stepper motors operate on battery voltage received through a fused ignition (run) circuit; however, the system will only operate when the headlamps are turned ON. The AFLS module monitors the condition and positioning of the leveling and swiveling stepper motors and circuits, and will store a Diagnostic Trouble Code (DTC) for any motor fault that is detected. Any DTC related to the AFLS can be retrieved from the AFLS module over the Controller Area Network (CAN) data bus.

The hard wired circuits for the headlamp leveling and swiveling motors may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the active electronic elements within the headlamp leveling and swiveling motors or the electronic controls and communication between other modules and devices that provide some features of the AFLS. The most reliable, efficient, and accurate means to diagnose the headlamp leveling and swiveling motors or the electronic controls and communication related to AFLS operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.