2012 Toyota Prius Owners Manual - Page 615

3 -1 . U sing t he a ir c ondit ioning syst e m a nd de fogge r Rear w indow and outside rear view mirror defogger sw itch Defoggers are used to defog the rear window, and to remove raindrops, dew and frost from the outside rear view mirrors. Turns the rear window and outside rear view mirror defoggers on/off The defoggers will automatically turn off after approximately 15 minutes. 3