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	BCM receives rear window defogger request signal from A/C amp. via CAN communication. BCM turns ON the rear window defogger relay based on the received signal. BCM transmits rear window defogger feedback signal to A/C amp. via CAN communication. BCm 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 in A/C switch assembly. A/C switch assembly transmits rear window defogger switch signal to A/C amp. via LIN communication. A/C switch assembly receives rear window defogger feedback signal from A/C amp. via LIN communication. A/C switch assembly turns the indicator light ON when detecting the operation of rear window defogger and 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.

OPERATION DESCRIPTION

A/C switch assembly transmits rear window defogger switch signal to A/C amp. via LIN communication line when rear window defogger switch is turned ON with the READY indicator lighting.
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 are supplied with power, and operate when rear window defogger relay turns ON.
A/C amp. transmits 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.

TIMER FUNCTION

BCM turns rear window defogger relay ON for approximately 20 minutes when rear window defogger switch turns ON. Rear window defogger and door mirror defogger operate only in the meantime.
When the rear window defogger switch is pressed during timer operation, the timer would be cancelled, and BCM turned rear window defogger relay OFF. The same operation also occurs, even if the electric motor switch is OFF.