The SxS Refrigerator Defrost Heater melts frost from the evaporator of the appliance throughout the automatic defrost cycle that occurs during normal operation. If the evaporator is freezing up and affecting the performance of the refrigerator, replacing the defrost heater may alleviate this issue. Remove the shelving and the rails in your freezer to gain access to the part behind the back panel. Installing this part will require basic hand tools, minor disassembly of the refrigerator and novice repair experience. Remember to unplug the refrigerator or shut off the house circuit breaker for the appliance before installing this part. Recommended Item: Consider replacing the Defrost Thermostat (item WP4387490) at the same time you complete this repair.