With the ignition switch in the ON position, the voltage runs through the DEF fuse to the rear defogger switch.

Whenever you press the rear defogger switch to the ON position, the closed contacts of the switch apply voltage to the following components:

Both indicators permanently ground at G203. The rear defogger grid permanently grounds at G300 (4-Door) and G402 (2-Door). The rear defogger grid is a resistive element that begins to heat as soon as you apply voltage. Both indicators will light when heating takes place.

The rear defogger switch does not incorporate an integral timing circuit. Place the switch in the OFF position in order to terminate the rear defogger operation.