2010 Toyota 4Runner Owners Manual - Page 332

3-1. Using the air conditioning system and defogger Rear window and outside rear view mirror defoggers Defoggers are used to defog the rear window, and to remove raindrops, dew and frost from the outside rear view mirrors. Before operating the defoggers, make sure the back window is completely closed. (→P. 94) Vehicles with a manual air conditioning system Turns the defoggers on/off The defoggers will automatically turn off after their operation time. The operation time varies depending on the ambient temperature and vehicle speed. Vehicles with an automatic air conditioning system Turns the defoggers on/off The defoggers will automatically turn off after their operation time. The operation time varies depending on the ambient temperature and vehicle speed. 310