The headlight system is composed of the driver's MICU, the passenger's MICU, the headlight and dimmer/flash-to-pass switches (inside the combination light switch), the left and right headlights, the lights-on indicator, and the high beam indicator.

Each MICU controls each side of the headlights with a built-in low beam control circuit and a built-in high beam control circuit based upon the position of the headlight and dimmer/flash-to-pass combination light switches. The taillights and license plate lights are controlled by the driver's MICU only.

When you move the headlight switch to the ON position and the dimmer/flash-to-pass switch to the low position, a ground signal is supplied to the No. 8 terminal of the driver's under-dash fuse/relay box connector R (24P). The driver's MICU then energizes the low beam control circuit, supplying battery voltage to the low beam of the driver's side headlight, turning it on. Also the driver's MICU sends the message to the passenger's MICU by B-CAN communication lines. The passenger's MICU then energizes the low beam control circuit, supplying battery voltage to the low beam of the passenger's side headlight, turning it on.

When you move the headlight switch to the ON position and the dimmer/flash-to-pass switch to the high position, ground signals are supplied to the No. 22 and No. 3 terminals of the driver's under-dash fuse/relay box (driver's MICU) connector R (24P). The driver's and passenger's MICUs then energize the each side of the high beam headlight control circuits, supplying battery voltage to the high beam headlights, turning them on.

When you pull the dimmer/flash-to-pass switch to the passing position, a ground signal is supplied to No. 21 terminal of the driver's under-dash fuse/relay box (MICU) connector R (24P). The driver's and passenger's MICUs then energize the high beam control circuits for as long as the switch is held, supplying battery voltage to the high beam headlights, turning them on.