Directions for testing a refrigerator defrost heater.
Before you begin to test your defrost heater, make sure you disconnect the appliance's power supply. The easiest way to do this is to unplug the unit from the wall. Alternatively, you could trip the appropriate switch in the circuit breaker panel, or you could remove the appropriate fuse from your home's fuse box.
Consult with an appliance repair technician if you do not feel you have the skill or the ability to successfully complete this repair.
- Locate your defrost heater. It can be located behind the back panel of the freezer section of your refrigerator, or under the floor of your refrigerator's freezer section. Defrost heaters are commonly located beneath a refrigerator's evaporator coils. You will have to remove any objects that are in your way such as the contents of the freezer, freezer shelves, icemaker parts, and the inside rear, back, or bottom panel.
- The panel you need to remove may be held in place with either retainer clips or screws. Remove the screws or use a screwdriver to release the clips holding the panel in place. Some older refrigerators may require that you remove a plastic molding before you can gain access to the freezer floor. Exercise caution when removing the molding, as it does break fairly easily. You could try warming it with a warm, wet towel first.
- Defrost heaters are available in one of three primary types: exposed metal rod, metal rod covered with aluminum tape, or a wire coil inside a glass tube. Each of these three types is tested in exactly the same way.
- Before you can test your defrost heater, you have to remove it from your refrigerator. A defrost heater is connected by two wires, and the wires are connected with slip-on connectors. Firmly grasp these connectors and pull them off the terminals. You may need a pair of needle-nosed pliers to help you. Do not pull on the wires themselves.
- Use your multitester to test the heater for continuity. Set your multitester to the R X 1 scale. Place the tester's leads on one terminal each. This should produce a reading anywhere in between zero and infinity. If your multitester produces a reading of zero, or a reading of infinity, then your defrost heater should most definitely be replaced. There are many different kinds of elements, and so it is difficult to say what exactly the reading should be for your defrost heater. But it definitely should not be zero or infinity. If it is, replace the mechanism.