Rear Defogger and Heated Mirrors
OPERATIONWhen the R. DEFOG (defogger) button is pressed, a serial data message is sent to the Body Computer Module (BCM). The BCM sends a serial data message to the HVAC Programmer, which then switches a ground to the Defogger Relay, allowing the coil to energize and the relay contacts to close. Voltage is then supplied from Circuit Breaker 24 through the relay contacts to the Rear Defogger, and Heated Mirror Defogger. The Rear Defogger and LH Outside Power Mirror Defogger are heated for 10 minutes. After the BCM times out, the Rear Defogger can be turned "ON" again by pushing the R. DEFOG (defogger) button. Additional time-outs are 5 minutes.
Whenever the Rear Defogger is "ON," the R. DEFOG Indicator lights. At the end of the time-out, the BCM sends information through the Data Line to turn the Rear Defogger Indicator "OFF." The defogger can be enabled only if the engine is running.