I have read all the posts on this common problem. My freezer is fine, fridge is warm. I have a maytag french door with drawer freezer. I pulled the panel off in the back of freezer, coils covered with block of ice, both fans work. I manually defrosted a few days ago, plugged back in and all works fine.although I suspect it will just ice up again. If it does, what parts should I check, or replace for this model?
First remove the evaporator cover in the freezer so you can see the coils.
Do not let them de-ice.
Manually force a defrost cycle, see the tech sheet
Now check the defrost heater to see if it is on.
Be careful you do not want to burn your fingers.
If the heater is on then the control board needs replacing.
If not on.
Unplug the unit.
Remove the wire for one side of the heating element (Item 15 in Section 5) from the wiring and measure it for continuity, usually around 20 ohms or so.
If the heater is OK
Remove one wire to the defrost thermostat (Item 31 in Section 5) and measure it, should be 0 ohms when frozen. Note that it opens just above freezing so must be frozen to check it. Also inspect it, if it is bulged at all replace it even if it measures OK.
If both the above are OK then odds are the board is toast.
Best way to test this is a live test to see if you have 120 volts across the heater/defrost thermostat combo (J1 Pins 1 to 5).
If you have voltage there then you may have a bad wire/connection.
If there is no voltage then the board is toast.