Hi there,

I do not anything about these cars and was just plunking!

FYI

When you unpluged the unit, its default is to go to that condition for safety reasons. All cars, to the best of my knowledge, are made this way.
Mechanically or Electronically, there has to be heat available to the occupants, if the car generates it.

It is designed to fail to heat, that way, if you were in the cold, say a bilzard, you would not freeze to death!

If you get too hot, then you can always roll down a window or just get out!

Phil