L200 L4-2.2L VIN F (2002)
Heated Glass Element: Description and Operation
The rear defogger system consists of a rear defog switch (part of HVAC control head), rear defog relay, located in the Left Instrument Panel Fuse Block
(LIPFB), Body Control Module (BCM) and rear defogger grid in the rear window. The coil side of rear defog relay is fed battery voltage from 10 A
IGN 3 fuse in LIPFB. Voltage flows through the coil, through circuit 193 to BCM where it is switched to ground when BCM receives the signal from
rear defog switch.
When the BCM grounds the coil side of relay, the relay is energized, and current flows through 10A DEFOG LED fuse in LIPFB, and through circuit
293 to rear defogger grid. The current flow through the DEFOG LED fuse flows to 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 circuit 550 (left mirror) at right body ground splice pack. Battery
voltage is fed to heated mirror relay. Current then flows through circuit 267 to mirror heater elements.
The BCM will keep rear defog relay energized for approximately 15 minutes first time the switch is pressed, and for approximately 7 1/2 minutes if rear
defog switch is pressed again.
