Circuit/System Description

Each headlamp assembly contains a high beam solenoid actuator that is controlled by the headlamp control module. 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 information regarding power mode, speed, steering angle, transmission gear selection, headlamp switch status, and turn signal/multifunction switch status. The high beam and flash to pass functions are contained within the turn signal/multifunction switch. The BCM provides the turn signal/multifunction switch with two signal circuits, the high beam signal circuit and the flash to pass signal circuit. When the low beam headlamps are ON and the turn signal/multifunction switch is placed in the high beam position, ground is applied to the BCM through the high beam signal circuit. The BCM responds to the high beam request by sending a serial data message to the headlamp control module. The headlamp control module interprets the serial data message from the BCM and responds by sending a serial data message to the left and right high beam solenoid actuators located in each headlamp assembly. Each high beam solenoid actuator is supplied with battery voltage and ground. When the high beam solenoid actuators receive a serial data message from the headlamp control module requesting the high beams, the solenoids open the high beam shutters illuminating the high beam headlamps. The headlamp control module communicates with the left and right high beam solenoid actuators via the LIN serial data circuit.