Heated Glass Element: Description and Operation

DUAL A/C, CJ2
With the ignition switch in RUN, voltage is supplied to the rear defogger relay coil. Depressing the rear defogger switch signals the HVAC programmer to provide a ground path for the rear defogger relay coil. The relay contacts close and provide voltage to the rear defogger and heated mirrors (if equipped). The "System On" LED lights, and the rear window and outside mirrors (if equipped) become warm, removing condensation from the glass surfaces.

The first time the rear defogger switch is depressed, the HVAC programmer's rear defogger relay control allows the rear defogger and heated mirrors (if equipped) to operate for approximately 10 minutes. Each time the rear defogger switch is pressed thereafter, the relay control resets to operate for 5 minutes. The rear defogger relay control resets to 10 minutes when the ignition switch is turned OFF, then back to RUN. The relay control also shuts OFF any time the rear defogger switch is pressed while the rear defogger and heated mirrors (if equipped) are already on.

ELECTRONIC A/C, C67
Operation of the electronic A/C, C67 rear defogger system is similar to that of the dual A/C, CJ2 system. With the C67 system, the rear defogger relay is controlled directly from the heater and A/C control assembly.