Robert N Deerfield , WI February 12, 2017 Appliance: Maytag Refrigerator ATB2232MRW00 Maytag Refrigerator Atb2232mrw00: Freezer icing up and not defrosting. How to replace Refrigerator Defrost Timer. Replaced Defrost timer, Heater element and Bimetal-Def. Since the Refrigerator was older and the parts are not that costly I just replaced them all since I was in there. 5 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 30-60 minutes