How to Replace a Refrigerator Defrost Heater

Before you replace your refrigerator's defrost heater, you should know for certain that it, rather than the defrost timer or defrost thermostat, is the cause of your defrost problem. A professional can check its ohm rating and tell you if the defrost heater is bad. But if you've got a hunch and want to save some money, here's how to perform a DIY replacement.


Find it


First a safety tip: unplug the refrigerator.


The defrost heater is usually located behind the back panel of the refrigerator's freezer or under the freezer bottom. If you know where the evaporator coils are, the defrost heater will be beneath them. Frozen food items should be removed and safely stored before you start looking.


To access defrost heaters, you'll need to remove either screws or retainer clips from a panel. Remove the freezer panel carefully, using a utility/putty knife to separate seams as necessary.


Remove the old defrost heater


A pair of slip-on connectors attach a defrost heater to the refrigerator's wiring. Remove these connectors from the terminals without pulling on the wiring. You might need the assistance of pliers or a screwdriver to get them off. Clips and screws might also be holding the defrost heater in place.


If the connectors and/or terminals are corroded, replace them.


Don't touch the tube


There are three kinds of refrigerator defrost heaters:

  • a glass tube containing a wire coil
  • an exposed metal rod
  • a metal rod covered with aluminum tape

If your defrost heater is the glass tube kind and you plan on testing it, do not touch the glass with your bare skin. Oil from your skin will cause the heating tube to burn hotter than is normal. If you accidentally touch the glass, clean it carefully with rubbing alcohol.


Testing and replacing


If you already possess the equipment to test a defrost heater, we'll assume you know how to use it. The VOM set reading (VOM for Volt Ohm Meter) should read between 5 and 20 ohms. If not, replace the defrost heater by reconnecting the wiring and clips/screws to a new defrost heater. However, if the test is good, you'll need to examine other parts of the faulty defrost system.