LW2 V6-3.0L VIN R (2000)
Rear Defogger: Description and Operation
Rear Defogger/Heated Mirrors
The rear defogger system consists of a rear defog switch (part of the HVAC control head), the rear defog relay, located in the Left Instrument Panel Fuse
Block (LIPFB), the Body Control Module (BCM) and the rear defogger grid in the rear window. The coil side of the rear defog relay is fed battery
voltage from the 10A IGN3 fuse in the LIPFB. Voltage flows through the coil, through circuit 193 to the BCM where it is switched to ground when the
BCM received the signal from the rear defog switch.
When the BCM grounds the coil side of the relay, the relay is energized, and current flows through the 10A DEFOG LED fuse in the LIPFB, and
through circuit 293 to the rear defogger grid. The current flow through the DEFOG LED fuse flows to the rear defog indicator in the HVAC control head
through circuit 683. If equipped with power/heated mirrors, current also flows from this fuse to the Right Instrument Panel Fuse Block (RIPFB) through
circuit 683, through the coil side of the heated mirror relay, to ground through circuit 450-right mirror or 550-left mirror at the right body ground splice
pack. Battery voltage is fed to the heated mirror relay. Current then flows through circuit 267 to the mirror heater elements.
The BCM will keep the rear defog relay energized for 15 minutes the first time the switch is pressed, and for seven and a half minutes if the rear defog
switch is pressed again.
