Rear Window Defogger System: Operation

The rear window defogger operates when ignition switch is in RUN or ACC position. When rear defogger switch is pressed, a momentary ground signal is sent to GEM, which grounds rear window defogger relay. When rear window defogger relay is activated, power from fuse No. 7 (40-amp) maxi-fuse in Central Junction Box (CJB) is supplied to rear defogger grid and outside heated mirrors. GEM turns the system on for 10 minutes, or until defogger switch is turned off or ignition switch is turned to LOCK or ACC position. For outside heated mirrorsdiagnose and repair, see appropriate POWER MIRRORS - SABLE & TAURUS article.