I would see aproblem running w/o an a/c in the winter because the compressor runs when the defogger/defroster is on to de-humidify the car and defog the windshield. I've been in a car with a non-working a/c in the winter and there was litterally ice on the windshield and in another car with a non-working a/c the window would just not defog or defrost.. well it wouldm but it took a long time.