I have just fitted electric mirrors on my car, but just got 1 question, What controls the heater element in mirror, as i would not want it on all the time and kill my battery.

Is it on same circuit as rear screen heter element.

As I understand it they only come on with the rear defroster.

However, they only warm up to about body temperature so would not feel noticeably hot to the touch.

Thank you.

just need to install electric windoes in rear now, should be fun (NOT)

Sometimes theyre controlled via a temp sensor for the whole car, does the locks etc in the winter, certain transit vans have them.