Rear Defogger: Description and Operation

The Electric Rear Window Defogger is standard equipment. A push button Rear Window Defogger Switch (2) located in the center console activates the rear window defogger. The switch is illuminated with instrumentation lighting for easy night time use. An LED (1) in the push button switch illuminates when the rear window defogger is working. When energized, a grid on the inside of the window heats up to help clear the outside surface of ice, snow or fog. The sideview mirrors are also equipped with heating elements that work in conjunction with the rear window defogger. For diagnosis of the heated mirrors, refer to Heated Mirrors-Electrical Diagnostics.




When the Rear Window Defogger Switch (2) is pressed with the Ignition Switch turned to the ON/RUN position, electrical current from Fuses 25 and 26 in the Underhood Accessory Fuse Block is applied to the rear window defogger grid. An LED (1) in the push button switch illuminates when the rear window defogger is activated.




On the Coupe model, the rear defogger grid is comprised of horizontal silver-ceramic grid lines (1) through the two vertical bus bars (2) on the glass inside surface. When the circuit is operating, the grid lines provide heat in the form of resistance. The heat is transferred to the outside surface to clear fog or snow. The grid lines comprise a parallel electrical circuit and are bonded to the glass permanently. Both the horizontal grid lines (1) and the vertical bus bars (2) are highly resistant to abrasion. However, it is possible for an open circuit to occur in an individual grid line resulting in no current flow. Care should be taken when cleaning the glass or removing foreign materials, decals or stickers. Normal glass cleaning solvents or hot water is recommended for cleaning. The grid lines and bus bars are repairable if they become damaged. For complete heated grid line and bus bar repair instructions see rear window defogger grid standard procedure.




On the Roadster model, the rear defogger grid is comprised of horizontal silver-ceramic grid lines (1) through the two vertical bus bars (2) on the glass inside surface. When the circuit is operating, the grid lines provide heat in the form of resistance. The heat is transferred to the outside surface to clear fog or snow. The grid lines comprise a parallel electrical circuit and are bonded to the glass permanently. Both the horizontal grid lines (1) and the vertical bus bars (2) are highly resistant to abrasion. However, it is possible for an open circuit to occur in an individual grid line resulting in no current flow. Care should be taken when cleaning the glass or removing foreign materials, decals or stickers. Normal glass cleaning solvents or hot water is recommended for cleaning. The grid lines and bus bars are repairable if they become damaged.