Voltage is available to the headlamp and panel dimmer switch at all times from the LIGHTING Fuse 8 through CKT 42 (RED). The headlamp and panel dimmer switch includes a self-resetting circuit breaker. The circuit breaker opens when the headlamp and panel dimmer switch draws too much current. When the circuit breaker opens, the circuit breaker interrupts the current flow. Without the current flow, the circuit breaker cools and resets automatically.

When the headlamp and panel dimmer switch is in the HEAD position, the headlamp and panel dimmer switch directs voltage to either the low beam headlamps on CKT 12 (TAN) or the high beam headlamps through CKT 11 (LT GRN). This depends on the headlamp and panel dimmer switch position. When the headlamp and panel dimmer switch is in the HEAD position, not only is voltage available for the headlamps, but the daytime running lamps (DRL) module receives a HEADLAMPS ON signal through CKT 10 (YEL). When the DRL module receives this signal, the module disables the DRL operation, if the ignition switch is in the RUN position, the BULB TEST position, or the START position.

When the headlamp and panel dimmer switch is in the HEAD position and the headlamp and panel dimmer switch is in the LOW position, voltage is available through the closed contacts of the headlamp and panel dimmer switch to the left low beam headlamp and the right low beam headlamp. Ground G112 supplies ground to the right low beam headlamp Ground G113 supplies ground to the left low beam headlamp in vehicles with the base headlamps and in vehicles with the quad headlamps. With both power and ground applied, the low beam headlamps light.

When the headlamp dimmer switch is moved to the HIGH position and the headlamp and panel dimmer switch is in the HEAD position, voltage is available through the closed contacts of the headlamp and panel dimmer switch, and the headlamp and panel dimmer switch to the DRL module, the left high beam headlamp, and the right high beam headlamp. With the headlamp dimmer switch in the HIGH position, voltage is available to the high beam indicator. With ground G103 in vehicles with gasoline engines, or ground G104 in vehicles with diesel engines, supplying a ground to the high beam indicator, the indicator lights. Ground G112 supplies a ground for the right high beam headlamp. Ground G113 supplies a ground to the left high beam headlamp. With both power and ground applied, the high beam headlamps light at full intensity.