2010 Jeep Compass heater

I have a 2010 jeep compass. Recently I have had to put in a new battery. Not sure when it started but it was after the battery. The heater and defroster is not working on the back window and the front only works on window defrost. I have gotten in the car and the windows are frosted on the inside. The coolant is full and working so it is not that it has been to cold to check the fuse(s) what else could it be and will it cost alot?

thanks Joan 416-551-6002