Headlamp Control Module: Description and Operation

When the headlamp switch is in the AUTO position, the auto headlamp module powers the head-lamps. A light sensor provides the input used by the module to determine if driving conditions warrant operating with the headlamps on.

Circuit A6 from fuse 10 in the Power Distribution Center (PDC) supplies battery voltage to circuit L26 through the circuit breaker in the headlamp switch. Circuit L26 powers the auto headlamp module. Circuits A6 and L26 are HOT at all times.

Circuit A6 also powers circuit 366 through fuse 12 in the fuse block. Circuit 366 is double crimped at the headlamp switch. The branch of circuit 366 from the headlamp switch connects to the auto headlamp module.

When the ignition switch is in the RUN position, it connects circuit A2 from fuse 13 in the PDC to circuit A22. Circuit A22 powers circuit F83 through fuse 19 in the fuse block. Circuit F83 connects to the auto headlamp module.

Circuit Z1 provides ground for the auto headlamp module. When the headlamp switch is in the AUTO position, it connects circuit L24 from the auto headlamp module to ground on circuit Z1. Circuit Z1 also connects directly to the auto headlamp module.

Circuit L109 from the auto headlamp powers the light sensor. Circuit L110 provides the input from the sensor to the auto headlamp module.

Circuit L90 from the headlamp switch powers the parking lamps and connects to the auto headlamp module.

When the headlamp switch is in the AUTO position, the auto headlamp module powers circuit F34. Circuit F34 connects to the dimmer switch. The dimmer switch connects circuit F34 to circuit L4. Circuit L4 powers the low beams of the headlamps.