System Description

SYSTEM DIAGRAM

Component	Function
A/C amp.	A/C amp. receives rear window defogger switch signal from A/C switch assembly via LIN communication and transmits rear window defogger request signal to BCM via CAN communication. A/C amp. receives rear window defogger feedback signal from BCM via CAN communication and transmits it to A/C switch assembly.
BCM	Receives rear window defogger request signal from A/C amp. via CAN communication. Turns ON the rear window defogger relay based on the received signal. Transmits rear window defogger feedback signal to A/C amp. via CAN communication. Performs the timer control of rear window defogger and door mirror defogger^*.
A/C switch assembly (Rear window defogger switch)	Rear window defogger switch is installed. Transmits rear window defogger switch signal to A/C amp. via LIN communication. Receives rear window defogger feedback signal from A/C amp. via LIN communication. Turns the indicator light ON when detecting the operation of rear window defogger door mirror defogger^*.
Door mirror defogger^*	Refer to Component DescriptionDoor Mirror Defogger.
Rear window defogger	Refer to Component DescriptionRear Window Defogger.
Rear window defogger relay	Refer to Component DescriptionRear Window Defogger Relay.
Rear window defogger condenser	Reduce the noise of rear window defogger operation.

*: With door mirror defogger

OPERATION DESCRIPTION

Turn rear window defogger switch ON when the engine running. Then A/C switch assembly transmits rear window defogger switch signal to A/C amp. via LIN communication line.
A/C amp. transmits rear window defogger request signal to BCM via CAN communication.
BCM turns rear window defogger relay ON and transmits rear window defogger feedback signal to A/C amp. via CAN communication when rear window defogger request signal is received.
Rear window defogger and door mirror defogger (with door mirror defogger) are supplied with power and operate when rear window defogger relay turns ON.
A/C amp. transmit rear window defogger feedback signal to A/C switch assembly via LIN communication line when rear window defogger feedback signal is received.
A/C switch assembly turns on the rear window defogger indicator light when rear window defogger feedback signal is received.
When remote engine start function is operated, according to the vehicle situation* A/C amp. transmits the rear window defogger request signal to BCM via CAN communication. For details, refer to Remote Engine Start Control.
note *: Depending on the vehicle situation (ambient temperature, in-vehicle temperature and sunload etc.) it is not operated.

TIMER FUNCTION

BCM turns rear window defogger relay ON for approximately 20 minutes when rear window defogger switch turns ON. It makes rear window defogger and door mirror defogger (with door mirror defogger) operate.
Timer is canceled after pressing rear window defogger switch again during timer operation. Then BCM turns rear window defogger relay OFF. The same reaction also occurs during timer operation, if the ignition switch is turned OFF.