Rear Defogger Switch: Description and Operation

Rear Window Defogger Switch - Typical:

The rear window defogger switch is a control and timing circuit integrated into a single panel mounted switch assembly. The rear window defogger switch is located in the accessory switch bezel on the instrument panel, just below the radio.

When the rear window defogger switch is turned to the ON position, current is directed to the rear defogger grid lines and the heated power mirrors (if equipped). The heated grid lines heat the glass to help dear the surface of fog or frost.

Energizing the rear window defogger relay provides electrical current to the rear window defogger grid and, if the vehicle is so equipped, the outside rear view mirror heating grids. An amber indicator lamp in the defogger switch illuminates to indicate when the defogger system is On.

The rear window defogger switch and indicator lamp cannot be repaired and, if faulty or damaged, the rear window defogger switch must be replaced.