InfoZone


Diagnosing the Problem: The Defrost Timer


Before you start to investigate this problem make sure that the power source to the refrigerator has been turned off. Make sure that you have a multitester, screwdriver, 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.

The defrost timer can be located either behind the lower kickplate, in the control panel or behind the refrigerator. They have four metal terminals that extend from the bottom.

Unscrew and pull the defrost timer so that the wires that are attached become disconnected. Pull firmly on the connectors and not the wires themselves.

Take your pen and labeling materials and attach them to each wire. You will need to note the results of the following tests on the labels to compare the results later on.

Take the multitester and set it for R X 1. Put one of the tester’s leads on the common (COM) terminal. This should be labeled “3’ or “C”. If you do not see a label, look for the one that coincides with the white wire in the connector plug. Keep this lead on the terminal at all times. Now take the other leads remaining to the terminals, one at a time.

The first two pairs tested should show a reading of zero or close to zero. The third pair test should show a reading of infinity.

Now go to the refrigerator’s timer switch. Turn it counter clockwise until you hear it click.

Take the multitester and test the terminals again. Make a note with your pen on the labels attached to the wires that this is now the timer switch test results. You should see the opposite readings from the results of the previous test. The pair of wires that showed a reading of zero should now show infinity and the pair of wires that showed infinity should now show zero.

If your tests do not show these results you need to replace your defrost timer.

After purchasing the new defrost timer, connect the wire connectors to the new timer. Screw the replacement defrost timer into place and replace the timer’s cover. Turn the refrigerator’s power back on.