How to Replace a Refrigerator Defrost Timer

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What You'll Need
Philipsorflathead screwdrivers
Replacement timer

Replacing a refrigerator defrost timer is a relatively simple repair that may save you money on calling an appliance repair person or replacing the entire refrigerator. The defrost timer tells the refrigerator thermostat when to turn off the cooling, usually about every six to eight hours, so that the defroster can run. This affects the efficiency of the refrigerator. If the refrigerator is not cooling, the timer may be stuck or broken and needs replacement. Here you will find the instructions needed to test and replace the component.

Step 1 - Locate the Timer

The timer could be located in a few different places on the appliance. First, unplug the refrigerator from the power supply. Most commonly, the timer is located behind the toe kick plate on the bottom front. Remove the kickplate. The timer is encased in either a white, black, or grey casing. If it is not behind the kickplate, check the back of the appliance, near the compressor. There are four wires going to the timer.

Step 2 - Test the Timer

The timer may not need to be replaced, but may only be stuck and failing to advance to the next cycle. Find the advance screw and turn it clockwise until you hear it click. Plug the refrigerator back into the power and stay close to the refrigerator so that you can monitor if it advances to the cooling mode. You will know it has advanced if you hear the compressor start up. If it does not advance, you will need to unplug the refrigerator again and replace the timer.

Step 3 - Remove the Timer

Remove the screws that secure the timer to the refrigerator. The wires will most likely be in a harness so that they can all be unplugged from the component together. If they are not, label the wires so that you remember how to reconnect them. Make a note of which terminal coincides with the white wire.

Step 4 - Test with Multitester

Using your multitester (set to X1), touch one of the probes to the terminal that coincides with the white wire. This terminal may be labeled with a "3" or "C". Hold the other probe to each of the three terminals. The ohms should stay at or near zero for at least one, and possibly two pairs of the terminals. At least one of the terminals should test at infinity. Turn the timer switch clockwise until you hear it click. Retest the terminals. Those that stayed at zero ohms should now test at infinity. If they do not, replace the timer with a new one.

Step 5 - Replace the Timer

Reattach the wiring to the timer either by plugging the harness back into the timer or reattaching the individual wires, in the order they were attached to the original. Secure the timer back to the refrigerator with screws. Replace any protective panels. Plug the refrigerator in and listen to make sure that the compressor comes on. Continue to monitor the refrigerator to ensure it is operating normally.