Voltage is available at all times to the headlamp switch and the high beam circuit breaker from the LIGHTING MaxiFuse® through CKT 42 (RED). Within the headlamp and panel dimmer switch is a 17A circuit breaker which resets automatically. Either circuit breaker opens upon heating due to an overcurrent condition. With the circuit breaker open, current stops, and the circuit breaker's thermal element cools. When sufficiently cooled, the circuit breaker closes.

The three-position headlamp switch has the following positions:

When the switch is in the HEADLAMPS position, voltage is available on CKT 10 (YEL) to the headlamp dimmer switch. The headlamp dimmer switch is part of the multifunction switch on the steering column. By pulling the multifunction switch lever up along the axis of the steering column, the switch changes selections. Repeated switch operations alternate between the high beam selection and the low beam selection.

With the selection of the low beams, voltage is available on CKT 12 (TAN) to the low beam headlamps. Because the headlamps are grounded, current flows through the low beam filaments and the headlamps illuminate.

With the selection of high beams, voltage is available on CKT 11 (LT GRN) to the high beam relay coil feed. Since the coil is supplied ground through CKT 150 (BLK) to G200 the relay is energized and the contacts close. Voltage is then supplied from the high beam circuit breaker through CKT 340 (ORN) through the closed contacts of the high beam relay to CKT 11 (LT GRN) to the high beam headlamps.

CKT 11 (LT GRN) also makes high beam voltage available at the instrument cluster for the lighting of the blue headlamp high beam indicator lamp. Since CKT 451 (BLK) grounds the instrument cluster's lamp circuits at ground G103 or ground G104, the indicator lamp lights when voltage is available.