When the ignition switch is turned to the RUN position, voltage is applied from the fuse B3- B4 through circuit 41 to the following components:

The rear window defogger relay receives battery voltage from the circuit breaker M1-M2 through circuit 1040. When the rear defogger switch is pressed, voltage is momentarily applied to the solid state timer, sending a ground signal to the rear window defogger relay through circuit 193. This action activates the relay which causes the relay contacts to close sending voltage from circuit 1040 through to circuit 293. This action sends voltage to the rear defogger grid which is receiving ground from G401 through circuit 450, causing the rear defogger grid to heat. This relay remains closed until one of the following conditions exist:

The defog cycle lasts 10 minutes when the following conditions exist:

Any further operation will result in 5 minute defog cycles. The defog cycle is reset to 10 minutes when the ignition switch is turned to the OFF position and back to the RUN position.

The defogger ON indicator is an LED that illuminates when the rear defogger is ON.

Radio Noise Suppression

A radio noise suppression wire is provided at connector C 3 of the rear window defogger grid to prevent the defogger from causing static during the operation of the radio.

Outside Rearview Mirrors

In addition to providing power to the rear defogger grid, circuit 293 also provides power to the fuse A5-A6 in the fuse block. From the fuse A5-A6 voltage is applies to the LH and RH outside rearview mirrors through circuit 267. These mirrors are connected to ground through circuit 750 and ground G301. This causes the defogger in the LH and RH Outside Rearview Mirrors to heat the mirrors and defog them. The operating time duration is the same as the rear window defog cycle.