Defogger

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A defogger is a device for clearing condensation from a window, which can also be useful for melting frost, ice, and snow that has collected on the window surface. They commonly exist in automobiles, in two basic varieties. Heating vents can be used to blow warm air over the window surface. Another type, commonly used on a vehicle's rear window, consists of an array of heating elements attached in thin strips to the window interior (known simply as a "heated rear window" in the UK). Some Ford cars also have very thin wires embedded in the front windscreen (windshield) glass to give rapid demisting before the engine is warm, although these sometimes fail on one side of the screen as the thin elements burn out. Ford call this system "Quickclear^TM".

In cold climates, it is often helpful to activate the defogger before using an ice scraper to clear off the car. Rear-window defoggers may operate on a timer, turning off after a predetermined amount of time, usually about 15 minutes, or may be linked to a warning lamp on the dash.