Rear Window Defogger System: Operation

The rear window defogger operates when ignition switch is in ON or ACC position. When rear defogger switch is pressed, a momentary ground signal is sent to GEM, which grounds defogger relay. When defogger relay is activated, power from 40-amp maxi-fuse in central junction box is supplied to rear defogger grid. GEM turns the system on for 10 minutes, or until defogger switch is turned off or ignition switch is turned to OFF or ACC position.