The defrost bi-metal thermostat shuts off the defrost heater if it gets hot enough to damage the evaporator. Set the multitester to the ohms setting X1. I have recently bought a defrost thermostat 12001937 on line and did a Continuity test right away. If they both are good, then you will need to replace the defrost timer WP2183400. It is located inside the control assembly. The best way to do this is to remove the thermostat from the refrigerator so you can control the temperature of the sensor. It's because inside every one of these appliances is a heater. Does anyone know of an easy way to test the defrost thermostat and fix it if it is not at the right settings? S ome defrost systems use a thermostat (a bi-metal switch) to prevent the defrost heater from overheating. As the metal cools, it makes a circuit again and the defrost heater starts heating again (as long as the defrost timer is in the defrost cycle). Note: Do not totally defrost the evaporator coils. There is a lot of misinformation on testing the defrost thermostat. If the connectors are corroded they should be replaced. Maybe it is something that I will have to call a repairman for. Use our step-by-step refrigerator repair guide to learn how to test your defrost thermostat. The seller claimed "this particular thermostat can not be tested as shown in you tube". Try warming it first with a warm, wet towel. It needs to be cold in order for you to test it. Most defrost thermostats CANNOT be tested in a glass of ice water because they have a closing temperature that is colder than 34°F.If you find that you have a bad defrost thermostat you can shop for a new one on our online store by searching with your refrigerators model number, or entering the part number off of the old defrost thermostat here: http://partsdr.com/appliance-type/refrigerator-parts/thermostat-parts/ We sell new OEM appliance parts for Whirlpool, Maytag, Kenmore, Amana, Estate, Roper, Frigidaire, Electrolux, Tappan, Westinghouse, Kitchen Aid, Jenn Air, Bosch, LG, Samsung, and more.If your refrigerator is not going through the automatic defrost cycle then you will need to test the defrost thermostat on your refrigerator. You will need to remove the rear panel inside the freezer by removing the screws. This heater melts any frost before it can accumulate and evaporates the moisture away. The defrost thermostat is usually located behind the back panel in the freezer section of the refrigerator, and it is usually clipped onto the evaporator coil.Get Social With us!https://www.facebook.com/PartsDrhttps://twitter.com/parts_drhttps://plus.google.com/+PartsDrCheck out our appliance repair forum: http://forum.partsdr.com/Check out our blog: http://partsdr.com/blog/Subscribe to our YouTube channel: http://www.youtube.com/subscription_center?add_user=thepartsdrIf you found this video helpful please click the thumbs up button and leave us a comment below. Step 4 Using the industrial hot air gun, apply heat to the thermostat. titans62 February 18, 2012 @SarahSon - That is odd that the freezer defrost thermostat wouldn't work right if the power went off. The little device that makes this possible is the bi-metal, or defrost, thermostat. Once you have diagnosed the problem we have the OEM replacement defrost thermostat that fits your appliance.. Before you begin to test your defrost thermostat, make sure you disconnect the appliance's power supply. Before you begin to test your defrost thermostat, make sure you disconnect the appliance's power supply. The thermostat is connected by two wires. During a defrost cycle, the defrost heater causes the metal alloy in the switch to warm and as … A bimetal strip is a laminate of two different metals. Removal of that molding can be tricky -never force it. Inspect the connectors and the terminals for corrosion. It is called a bi-metal thermostat because at its heart is a strip made of two metals with different expansion rates, which when heated begins to curve. The panel may be held in place by retainer clips or screws. If the thermostat does not pass this test it should be replaced. If one of these are open, they are bad. Caution: Please read our safety information before attempting any testing or repairs. DISCLOSURE: This post may contain affiliate links, meaning when you click the links, we may receive a commission. You will find the defrost bi-metal switch fastened to the top right, or left corner of the evaporator coil. If you decide to remove it, you do so at your own risk - it is prone to breaking. You will find the defrost bi-metal switch fastened to the top right, or left corner of the evaporator coil. Test the thermostat for continuity using a multitester. The easiest way to do this is to unplug the unit from the wall. It is usually located at the back of a side by side freezer or under the floor of a top freezer. The little device that makes this possible is the bi-metal, or defrost, thermostat. During a defrost cycle, the defrost heater causes the metal alloy in the switch to warm and as it does it curls back and breaks the circuit. I wonder if that is what is always happening to my upright freezer, though. The defrost thermostat, a bi-metallic switch, controls the temperature rise in the freezer compartment during the defrost cycle. The defrost heater will be located below the evaporator coils and the bi-metal thermostat will be located clipped to the upper left hand or upper right hand corner of the evaporator coils. Place a probe on each terminal. This video shows the proper way to test your defrost thermostat. The defrost thermostat is located near the defrost heater and is wired in series. When the frost buildup is excessive, the refrigerator can't cool well. When the refrigerator stops going through the automatic defrost cycle the refrigerator will not cool properly because the frost will block the air flow on the evaporator coil and cause the cold air to stop circulating.