My 2 cents on this awful overpriced (Whirlpool Kitchen aid model/s) We have the unfortunate pleasure of having to maintain these horrible units, 14 of them in a beachside multiple unit complex. The units where installed in 2014-2015 and since then I think I have had to replace parts on just about all of them. From ice makers, to water valves (freezing in the roof, that's another story) Evaporator fan motor kits, led light bulbs and driver boards, main boards, drawer temperature controls and wiring harness <--complete stupid design! 2 compressors, a few filter housings, door switches, well you get the picture. I'll admit I am no genius on this model but getting close. With all that said the most common problem we see with these is gasket leaks (or freezer door not shutting proper) It causes the freezer coil to ice up after about 2 weeks and it wont do a defrost. The tech sheet is pretty useless because the LO/LD option does not work on any of the 14. <-- and if there is a magic selector button to choose this option I sure haven't found it! One thing I have found on this model that triggers defrost automatically is that the coil mounted thermistor MUST get cold enough. Thus meaning that snow/frost will not make it work, it has to be at subzero temperatures made by ice and normal coil temperatures. And I believe that until the main board see's this temperature it will assume not to do a defrost and run cooling continuous, just like the 'old school' GE models that was running low on Freon. Once again <--stupid design, that should be timed also, just in case this happens accidentally (like leaving the door ajar) Moral of my rant, check for air leaks, its VERY important on this model!, Use a bright led light in each compartment when the room is dark if you must, if you can see light, there is your problem......hope this helps, but save yourself time, the evap fan kit (freezer) and main board are actually pretty rare to fail from my findings, so please check the poorly designed tech sheet.......whoever heard of letting a ice maker overfill, God what a joke! and look for gasket, rail, heater failures all first! thanks for reading D!