Headlamp Operation

The battery fuse supplies the following to cavity 87 and cavity 30 of the low beam relay:
^ Battery voltage
^ 175A of current potential

The current is the power provided through the relay contacts to each HID ballast when the relay is closed. The low beam relay is controlled by a 12-volt input supplied to cavity 85 by one of the following components:
^ The headlamp switch when the headlamp switch is in the HEAD position
^ The Body Control Module (BCM) when the headlamp switch is in the AUTO position

The relay coil is permanently grounded through cavity 86 at ground G102. When the headlamps are turned on, either from the headlamp switch or the BCM, the following actions occur:
^ The relay contacts close.
^ The battery supply voltage is switched through the RT LOW and LT LOW fuses in the UBEC to each HID ballast.

Each ballast has a separate ground.