Before you start to investigate to see if there is a problem make sure that the power source to the refrigerator has been turned off. Make sure that you have a multitester, screwdriver, a pen and something to label the wires.
Most multitesters are hand-held with an LCD display. They have two wires referred to as leads. One wire is red and the other is black, with metal tips called probes.
The multitester will be your aid in diagnosing electrical issues and you will also use it to measure resistance. The way this is done is by measuring the ohms - resistance of the wire to flow of electricity. The range of ohms goes from zero to infinity. A reading of zero ohms shows that it is very easy for the electricity to flow. A reading of infinity means there is no path for the electricity to go through.
Remove all contents from the freezer, including any shelving, ice maker parts and the rear, back and bottom panel.
Some older refrigerators require that you move plastic molding before you can gain access to the freezer floor. If your refrigerator unit is older and requires this step, try warming the molding with a wet cloth before removing. When the molding is hard and dry it tends to break easily.
There are three types of defrost heaters: exposed metal rod, metal rod covered with aluminum tape or wire coil inside a glass tube. However, you will test each kind in the same way.
In order to test the defrost heater you need to first remove it from the freezer. This part is connected by two wires that are connected to slip-on connectors. Pull on the connections until they are no longer connected to the terminals. Do not pull on the wires themselves.
Now set the multimeter to the R X 1 scale. Take the tester’s leads and put on one terminal each. The reading should be between zero and infinity. If however you get a reading of zero or a reading of infinity then you must replace the defrost heater.
Remove the damaged defrost heater. Be careful not to touch the outer glass tube with your bare fingers. This can result in oils from your hands to cause the heater to burn hot and damage your freezer or heater. If you do touch this part with your hands, quickly wipe the area with rubbing alcohol and a clean cloth.
Now install the replacement defrost heater and connect the wires. Remember to replace the access panel and restore the power to the unit.
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