Hi I have a Maytag Amana Refrigerator Model no:XRSS287BB. The problem is that the fridge keeps freezing. The freezer works fine but the fridge gets too cold at -12.Ice builds up on the shelves etc. Any help would be really appreciated. I am an appliance repairer but this one being electronic is eluding me. I am thinking it might be the thermistor or the board or both but I could be wrong. Please help.