This page will help you diagnose and repair a problem with the automatic defrost system on your frost free refrigerator.

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REFRIGERATOR DEFROST CYCLE DIAGNOSIS

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NOTE: Most newer refrigerators use electronic devices to control the defrost system. If your refrigerator does not have a defrost timer, do not attempt this diagnosis procedure.

  • 1) Unplug the refrigerator.

  • 2) With the freezer frozen down, (it must have been running at least a couple of hours to give the contacts in the defrost thermostat a chance to get cold and close) remove the evaporator cover (the cover in the freezer that covers the cooling coil)

  • 3) Plug the refrigerator in.

  • 4) Locate the defrost timer and, with a screw driver, turn the timer to the defrost mode. ( There is a slot on the timer that the screwdriver will fit in. Turn it clockwise. The refrigerator will stop running when it goes into the defrost mode.)

  • 5) Wait about 5 minutes, then see if the defrost heater is heating. It will get VERY HOT, so be careful! If it is heating, the defrost heater and defrost thermostat are good. The timer should be replaced.
    YOUR PROBLEM SHOULD NOW BE SOLVED!

  • 6) If the heater is not heating, then the timer is probably good. (While this is not true ALL of the time, in my years of experience I have seen this NOT true only a few times. You could still have a bad timer, but is unlikely)

  • 7) UNPLUG THE REFRIGERATOR!

  • 8) Use a hair dryer to defrost the evaporator (cooling) coil.

  • 9) Visually inspect the defrost heater. Check for a broken or burned area on the heater. Replace the heater if you find this.
    YOUR PROBLEM SHOULD NOW BE SOLVED!

  • 10) If you do not have a multi-meter, skip to 13. If you have a multi-meter, check the resistance of the heater by disconnecting the wires from both end of the heater and, with the meter set to "OHMS", put one meter lead on each end of the heater.

  • 11) If you get no reading on the meter (nothing happens on the meter), replace the heater.
    YOUR PROBLEM SHOULD NOW BE SOLVED!

  • 12) If you get a resistance reading, replace the defrost thermostat. (See 6 above.)
    YOUR PROBLEM SHOULD NOW BE SOLVED!

  • 13) If you do not have a multi-meter, make sure the refrigerator is unplugged, then locate the defrost thermostat. It is a round, quarter sized part with two wires coming out if it. It usually mounts directly to the evaporator coil.

  • 14) Make a note of how each wire is attached to the thermostat.

  • 15) Remove all wires from the thermostat.

  • 16) Using a wire nut, connect together ALL of the wires that WERE attached to the thermostat together. This bypasses the termomostat for the purpose of testing it. DO NOT LEAVE IT BYPASSED UPON COMPLETION OF THE REPAIR!!!

  • 17) Plug the refrigerator back in. Make sure the timer is still in the defrost mode.

  • 18) Wait a couple of minutes, then check to see if the heater is heating. It will get VERY HOT, so be careful.

  • 19) If the heater is heating, replace the thermostat.
    YOUR PROBLEM SHOULD NOW BE SOLVED!

  • 20) If the heater is not heating, replace the heater. (See 6 above)
    YOUR PROBLEM SHOULD NOW BE SOLVED!


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