I think I have the same, or similar problem. I have a 2002 sebring convertable, and my problems started after I had left the mirror lights on over night and drained the battery. left the battery attached in the car and connected a charger. From notes I'm finding on the web, it seems a draining battery leaves the car's computer in a random state and you need to disconnect the battery for about 1 hr and reconnect. did you get your heater problem resolved ? If so, can you share the fix. Thanks, Ron