Electric Rear Defrost
STANDARD HVACWhen the rear defrost input circuit 292 to the BCM is momentarily switched to ground (as when the rear defrost switch is pressed), the BCM will respond by grounding circuit 193, the coil of the rear defrost relay.
This action energizes the rear defrost relay providing power to circuit 293- rear defrost heater elements, circuit 683- heated mirror relay coil and circuit 683- rear defrost LED telltale. Momentarily switching circuit 292 to ground again will result in the BCM turning the rear defrost relay Off.
AUTOMATIC CLIMATE CONTROL
The request for rear defrost is received by the BCM over serial data (class II). The BCM will energize the relay which send voltage to the rear defrost grid
The first time in an ignition cycle that the rear defrost is activated, rear defrost will remain On for 15 minutes or until the ignition switch is turned OFF. If rear defrost is activated again during the same ignition cycle, rear defrost will remain On for 7.5 minutes or until the ignition switch is turned Off.