While the front windshield defroster is part of the car HVAC system and blows hot air through vents on top of the instrument panel to clear ice and fog, the rear defroster uses electrical current to produce heat to clear the back window. The lines are actually thin wires made out of conductive materials like metal or electrically conductive resins, and they are either attached to the inside of the glass or embedded within the glass during manufacturing. Sometimes, youll find similar defroster...
