I just bought 1997 ford crown victoria the ac was working I turned on the heat because it was cold inside of car to get warm then the next day i turned on the ac and now it only blows hot air why?

It's possible you were duped by the seller, who may have charged the system just before you tested the car, and the leak is so bad it ran out overnight. I'm not accusing, but it's the one possibility that comes to mind. You could verify by charging again to see if it works again after charging and then stops again the next day.