How to Repair a Refrigerator Defrost Heater

refrigerator in kitchen
  • 2 hours
  • Intermediate
  • 50
What You'll Need
Warm towel
Replacement defrost heater

Sometimes the refrigerator cools too much, and sometimes it does not cool at all. Often this is caused by a broken defrost heater, the component set to regulate the temperature of the fridge in order to keep food cold. All refrigerators will have a defrost heater. If your appliance is not working, it is not necessary to get a new refrigerator but rather to fix or replace the broken defrost heater.

Step 1 – Location

To replace the heater, you need to first unplug the fridge and locate its defrost heater. Before accessing the heater, take out any food so that there is plenty of room to work. The heater can be located in one of two places: underneath the freezer door floor or behind the refrigerator's back panel.

Step 2 – Timer

Sometimes it is only the timer that is broken, so look for the advance screw. Turn this clockwise to advance the timer. Wait about 30 minutes to see if any change occurs. If the timer has not advanced, then it should be replaced. If replacing the faulty timer still does not cause the defrost heater to work, then the defrost heater is most likely broken and will need to be replaced.

Step 3 – Temperature Setting

Check that the temperature setting has not accidentally been changed. Depending on where the dial is, a jar or a container that has shifted may have changed the temperature to a higher temperature. Reset the temperature and listen for the defroster to start. If it does not immediately start, then there are additional problems to be solved within the unit.

Step 4 – Air Flow

Make sure that the airflow is good by ensuring the vent is not blocked or clogged by any spilled substance. This can cause the system to malfunction, preventing the interior of the refrigerator from reaching the desired cool temperature. You should always make sure the vents are not blocked and that air can easily circulate in the fridge and freezer.

Step 5 – Condenser Coil

These coils should be cleaned at least once a year, as particles in the air can become deposited on the coils and cause operating problems when the buildup is thick enough. This can easily be cleaned by vacuuming the coils and brushing away any dirt with a rag or a brush. In fact, a narrow paintbrush is perfect for getting rid of dirt in hard to reach places.

Step 6 – Wire Connections

Make sure that the wires are not twisted or kinked. In the case that the wires have a secure connection, use zip ties or the original connectors to keep them in place to avoid future problems. Make sure that all the wires are properly covered, as the heat and condensation will cause issues with the electrical connections.

Step 7 – Thermostat

When all else fails, the defroster may not be working properly because the thermostat in the refrigerator is probably faulty, not allowing the defrost heater to detect the proper temperature. Pull out the thermostat, near the temperature switch, and see if the heater works when the thermostat is out. Sometimes the thermostat can be completely broken or a short circuit may have occurred in the wiring. Replacing the thermostat should activate the defrost heater.

TIP: If you are not comfortable doing appliance repairs yourself, then talk to a professional. This is a simple repair that the repairman can have it fixed quickly and easily as long as the part is in stock. It will cost about $200, depending on the refrigerator model.