The GE WR50X10071 Defrost Bi-Metal Thermostat is a basic thermostat for GE refrigerators, and is used in a huge number of GE Freezer-Top refrigerators. The temperature range is from 64-41*F with 24-inch leads.
If this part is defective, the defrost heater simply will not run. The only way to test this part is to ensure its within the temperature specification, and use a multimeter to test continuity. A tell-tale sign of a defective defrost sensor is a swollen black cap, indicating failure.
The WR50X10071 model replaces WR50X10076, WR50X22303 and is a cross-referenced model to WR50X10021.
Also available is the WR50X10068 which replaces the WR50X10015, WR50X10017, WR50X10018, WR50X10028, WR50X10051, WR50X10052, WR50X10053, WR50X10054, WR50X10074, WR50X10075, and WR50X10079 models.