The heat and air in my car all of the sudden stopped working right. It would blow full blast sometimes, even if I tried to turn it down and then sometimes it wouldn't work at all. Then it wouldn't cut off even when I turned the car off and I had to take the fuse out so it wouldn't run my battery down. I obviously have to put it in the shop but I was wondering what the problem was and how much it might cost to get it fixed?