Principles Of Operation

Headlamps

Principles of Operation

Low Beams

The headlamp switch is supplied voltage when the ignition is in RUN. When the headlamp switch is placed in the HEADLAMPS ON position, the low beam relay is energized and voltage is provided to the headlamps. The low beam relay is supplied voltage from 2 sources (the low beam interrupt relay and the high beam relay when neither are energized).

High Beams and Flash-to-Pass

The Instrument Cluster (IC) controls the function of the high beams and the flash-to-pass request. The IC monitors the multifunction switch for a flash-to-pass or high beam request by sending voltage signals to the multifunction switch. When the multifunction switch is in the FLASH-TO-PASS position, the voltage signal is routed to ground. When the multifunction switch is in the HIGH BEAM position, both voltage signals are routed to ground to indicate a request to change from the low beams to the high beams, or to change to the low beams if the high beams are on.

When the headlamps are on and the IC receives a request for high beams, the IC energizes the high beam relay and the low beam interrupt relay. The low beam interrupt relay disables voltage to the low beams and the high beam relay provides voltage to the high beams.

When the ignition is in RUN and the IC receives a request for the flash-to-pass (for as long as the multifunction switch is held in this position), the IC energizes only the high beam relay and provides voltage to the high beams.