Thanks!
Yes, I am worried about the high current and high voltage at the terminal as well. I am thinking about putting the board inside the enclosure of the heater, where not much heat is absorbed. Probably into one of the foots.
Than I need to think about the heat ratings of the coil. As the temp goes up, so does the resistance of the coil and the opperating current will go up as well, when doing that solution.
But it will be the neatest. Just having a cable coming out of the heater without anything more attached to it. I want to use the 230V current to power the board as well and was thinking about using a small apple charger, like this:
to transform it down to the operating voltage/current the board needs.
@Rerouter:
I won't do a temperatur control. Just switching it on 10 mins before I get into the car via my smartphone, so it is warm and the windows are icefree