Rear Window Defogger Switch: Description
WARNING: This page is about a different car, the 2003 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.
The rear window defogger switch is installed in the instrument panel HVAC control head assembly. The momentary-type switch provides a hard-wired ground signal to the HVAC control head each time it is depressed. The instrument cluster rear window defogger timer and logic circuitry responds by energizing or de-energizing the rear window defogger relay.