Paul C Willits , CA February 08, 2018 Appliance: Samsung Refrigerator RF263BEAESR/AA-0000 Samsung Refrigerator Rf263beaesr/Aa-0000: Was freezing up bad. How to replace Refrigerator Defrost Thermostat. I replaced heater metal,Thermo bi-metal and for good measure I replaced the sensor also. I also cleaned the unit throughout the bottom. It has worked like new now. 1 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 30-60 minutes