How to test a refrigerator defrost heater

Written by nicole desrosiers
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How to test a refrigerator defrost heater
Performing regular checks on your refrigerator defrost heater can extend the life of your appliance. (contents of fridge image by Christopher Hall from

A defrost heater on a refrigerator is essential to its functionality. If your refrigerator's defrost system is not functioning properly your refrigerator may reach temperatures that can freeze and spoil your food and damage the unit itself. It is important to check this system regularly to maintain the life of your refrigerator. Fortunately, learning to test a refrigerator defrost heater is a fairly simple process that most people can do themselves.

Skill level:

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Things you need

  • Screwdriver
  • Multimeter

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  1. 1

    Disconnect your refrigerator's power supply. Attempting to work on the unit while it still has an electric current running to it can damage the system and can be hazardous to your safety. Disconnect the power supply by simply unplugging it from the power socket or by turning off the breaker that controls that circuit.

    How to test a refrigerator defrost heater
    Unplug your refrigerator to avoid possible electrocution. (plug image by Roman Sigaev from
  2. 2

    Remove the contents of your refrigerator's freezer. You are going to have to move any items that will prevent you from having full access to the defrost heater. Frozen foods can be piled into a clean sink temporarily until this process is complete. Checking the defrost heater should only take a few minutes so there is little to no risk of your food spoiling.

    How to test a refrigerator defrost heater
    Empty the freezer of all food products to give yourself more space to work. (Frozen peas image by Acqua Alta from
  3. 3

    Locate and remove the defrost heater. In most standard refrigerator models, it is located behind a control panel at the back of the fridge or underneath the floor of the freezer over its evaporator coils. Disconnect the panel that connects it to the refrigerator by using a screwdriver to remove any screws that hold it in place. Under this panel, the defrost heater is connected to the unit by two wires with slip on connectors. Pull the connectors firmly to disconnect them from the terminals. Remove the heater and place it on a steady surface.

    How to test a refrigerator defrost heater
    Use a screwdriver to remove screws holding the panel over the heater in place. (a screwdriver image by alri from
  4. 4

    Test your defrost heater using your multimeter. Set your meter to the X1 ohms setting. Using the two probes on your multimeter, place one on each of the heater's terminals and test as normal. A defrost heater's reading will vary from unit to unit, but a working heater will read a positive number between zero and infinity. However, if your multimeter reads either zero or infinity, contact a heating and cooling professional to help fix your system as soon as possible.

    How to test a refrigerator defrost heater
    Set your multimeter to the X1 ohms setting to test your defrost heater. (digital multimeter 3 image by dinostock from

Tips and warnings

  • If you having issues with this process or feel that it may take longer than expected, keep a cooler handy to prevent perishables from spoiling.
  • Always remember to disconnect the refrigerator from its power source to prevent the threat of electrocution.

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