Model Number: MFF2557HEW
Brand: Maytag
Age: 6-10 years
Periodically, the refrigerator gets warm, while the freezer remains cold. I have done the manual defrosting and it seems to work for a long time (months), but the problem eventually comes back. This time, I rented a refrigerator and my wife is away for a week. So the following is what I have been doing after watching a number of online videos.
Before replacing the control board, I tried the diagnostic mode. The first test showed as a failure (Defrost Thermostat Diagnostics). I then replaced the control board with a new control board "Jazz" P/N 67006740 directly from Maytag. I redid the test, the result "Test 1 OPEN" (still a failure). The freezer was partially iced up, so when I cut out the "Defrost Terminator" (the defrost thermostat) and placed it in the freezer of a rental refrigerator and packed it into snow ice, after one hour, it showed as still open. At that point, I ordered a new defrost thermostat from partsdr.com.
This morning, I retested the frozen thermostat and it tested "CLOSED" (Zero ohms indicating that it was closed). While encased in ice, I respliced the defrost thermostat back into the circuit, redid Test 1 (Defrost Thermostat Diagnostics) and it was now closed. I had a voltmeter connected to the wiring that would connect to the heater and the voltage would measure about 23 volts. When I ran Test 1, then the voltage would show as 123 volts. When I cycled it, it would change between the 23 and 110 volts. This all seems normal and functioning.
I checked for continuity of the heater and it shows 0 ohms.
What should I be checking for at this point.