Kelvinator Cyclic Defrost Fridge Thermostat - Part # 500641, 077B6075Danfoss Kelvinator, Frigidaire Cyclic Defrost Thermostat. Part No. 500641, 077B6075. Suits older Westinghouse, Kelvinator and Frigidaire two door cyclic defrost fridge freezers and single door cyclic defrost refrigerators without a freezer compartment where the thermostat is mounted with the light on the side wall of the fridge compartment. This thermostat is supplied bare, without knob or mounting hardware. The knob shaft is a fitting with a large