058966-000 Defrost Terminator, Thermostat for VikingNew 058966 000 (DEFROST TERMINATOR, THERMOSTAT) Sub from PB910259, 10442407. This defrost termination thermostat 058966 000 senses evaporator temperature and stops the defrost heater when the evaporator has warmed enough, helping prevent over defrost and protecting the refrigerator's cooling components. By cutting power to the defrost heater once the frost is cleared, it prevents overheating and ensures your Viking fridge or freezer maintains optimal