Rear Defogger: Description and Operation

CAUTION: Grid lines can be damaged or scraped off with sharp instruments. Care should be taken in cleaning glass or removing foreign materials, decals or stickers. Normal glass cleaning solvents or hot water used with rags or toweling is recommended.

The rear window defogger system, also known as electric backlight (EBL), consists of two vertical bus bars (1) linked by a series of grid lines (2) fired onto the inside surface of the rear window (3).

The EBL system is turned On or Off by a switch and a timing circuit integral to the A/C-heater control located at the center of the instrument panel.

Circuit protection is provided by two cartridge fuses located in the integrated power module (IPM). One fuse is for the control circuit and the other fuse is for the heated grid circuit.




The electric backlight (EBL) system is controlled by a momentary switch (1) located in the A/C-heater control (2) on the instrument panel. When the rear window defogger switch is pressed to the On position, the A/C-heater control energizes the rear window defogger (EBL) relay and the heated mirror relay, which then directs battery current to the rear defogger grid lines and to the heated side view mirrors. The grid lines heat the glass to help clear the rear window and side mirror surfaces of fog or frost.

An amber indicator (3) in the rear window defogger switch will illuminate to indicate when the EBL system is turned on. The A/C-heater control contains the EBL system control circuitry including the timer logic.

NOTE: The EBL system turns off automatically after approximately ten minutes of operation.

The EBL system will be automatically turned off after a programmed time interval of about ten minutes each time the rear window defogger switch is pressed. The EBL system will automatically shut off if the ignition switch is turned to the Off position, or it can be turned off manually by pressing the rear window defogger switch a second time.

Repair of the rear window defogger grid lines, bus bars, terminals or pigtail wires can be accomplished using the Mopar Rear Window Defogger Repair Kit (Part Number 04549275) or equivalent.