For 1990-2009 cars

### Rear Window Defogger System Components

The optional rear window defogger system consists of the following components:

• | A rear window defogger switch

• | A rear window defogger relay/timer

• | A rear window that has a number of horizontal ceramic silver compound grid lines

• | Two bus bars that are attached to the inside surface of the rear window.

The supply voltage terminal is soldered to the bus bar on the right side and the ground terminal (1) is soldered to the bus bar on the left side.

### Rear Window Defogger Operation

When the ignition switch is in the ON position, ignition voltage is applied to the defogger relay, through the DEF fuse.

When the rear defogger switch is depressed, a ground signal is provided to the defogger relay through the switch to G200. This activates the timer circuit and relay, which provides battery voltage through the closed contacts of the relay to the indicator in the switch and to the rear defogger. The rear defogger is a resistive element grounded at G401 and begins to heat as soon as voltage is applied. The indicator is grounded at G200 and illuminates as soon as voltage is applied.

The defogger relay incorporates an integral timing circuit. The timer circuit will terminate the rear defogger operation after 15 minutes. Defogger operation may be cancelled before the cycle ends by depressing the defogger switch, or by turning the ignition switch to the OFF position.

The rear defogger switch may be depressed for additional cycles depending on the following conditions:

• | Vehicle speed

• | Outside window temperature

• | Atmospheric pressure

• | Number of passengers