2013 A3 Front Defrost Control

Does anyone know if I can control the Front defog on an automatic climate control (SLine dual heat Auto control) via an alarm. A guy is doing an install and is going to power the rear defrost as an option but thinks the fron is CAN Bus connected with the Comfort Module. Anyone have a wiring diagram or know if this can be done as I would like the car to start and defrost front and rear windows. Thurs 20th is the install date so I need a quick answer.

Well did some tests and if I remember the defrost setting will stay active when the car is turned off; I would still like to have the option to activate it from the remote start remote!!