The refrigerator/freezer defrost system can be checked by
manually initiating a defrost cycle. There
are two methods of initiating the Adaptive Defrost Control (ADC) Test Mode.
First Test Method:
1. Turn the thermostat off for 15 seconds.
2. Turn the thermostat on for 5 seconds.
3. Turn the thermostat off for 15 seconds.
4. Turn the thermostat on for 5 seconds.
5. Turn the thermostat off for 15 seconds.
6. Turn the thermostat on for 5 seconds.
7. Turn the thermostat off.
In 3 to 8 seconds the ADC should turn on the defrost heater (with the bimetal
closed). NOTE: The test mode will terminate when the bimetal opens. If the
refrigerator/freezer is already in defrost, Test Mode can be terminated by
unplugging the refrigerator/freezer from the wall outlet and waiting 30 seconds
before plugging it back in. The refrigerator/freezer should immediately go into
cooling mode if the thermostat is closed.
If this first test procedure fails to make the ADC initiate a defrost cycle, try
the following procedure to make the ADC begin the Test Mode.
Second Test Method:
1. Disconnect the refrigerator/freezer from the wall outlet for at least 30
2. Turn the thermostat off.
3. Reconnect power to the refrigerator/freezer.
Within 3 to 8 seconds the ADC should turn on the defrost heater (with the
bimetal close). If the unit fails to go into the defrost mode during this test,
the problem may not be with the ADC. A defective bimetal may be the cause of the
failure. The ADC will only go into a test mode if the bimetal
is closed. If the ADC senses an open bimetal it will return to the cooling mode
within 3 to 8 seconds.
HELPFUL HINT: Upon entering the Test Mode, the relay mounted on the ADC board
should turn off the compressor and turn on the defrost heater. Listen for the
relay to click.
If the relay clicks one time when entering the Test Mode, check for
continuity in the defrost heater.
If the relay clicks two times, check for an open bimetal.
A helpful schematic of the wiring can be found at the following website link http://www.applianceaid.com/images/mayadaptive-defrost.JPG
The control board will look something like this picture =>http://www.applianceblog.com/archives/MaytagAdaptive.jpg
This is all happening in the fresh food compartment, up top which is where you will find it. It is very failure-prone, so you are definitely not the first, the relay in it is usually the failure. Be sure
to unplug the fridge before disassembling or you could get a nasty
shock. Been there, done that.
If you don't defrost the fridge manually, then you should let it
defrost on its own by turning it off and leaving the freezer door
open. Usually, I take apart the freezer and defrost the evaporator.
But, if you can get by without it for a few days, just let the fridge
defrost on its own.