It might be the heating element that went bad. I know it sounds weird, but I had that happen to my fridge earlier this year. It's very easy to check this part. It's in the freezer side. You have to remove most if not all of the shelves and remove the panel in the back of the freezer. The heating element is probably toward the bottom held in by a couple screws. Not sure what brand yours is or if it makes a difference, but I have a GE fridge that's about 4 years old. The heating element was approximately $25, don't remember exactly, but it wasn't very expensive. I got it from Dayco Appliance Parts at 71 and Weber. Hope this helps.