How cold should each side be? My diffuser is open no matter what I set the controls to. I took off the back panel inside the freezer in the back/bottom. There is some frost on the coils....should there be "none"? The temp in the freezer is 20 and the refrigerator is 42. I had the unit unplugged for 12 hours and cleaned all the dust bunnies, ran hot water through the drain tube in the freezer...all clear. Better than before temp wise. Help?