Very easy with tech advise (Dawn) she help me out... I had already did some troubleshooting on defrost thermostats and thermistors before guessing on what was wrong. I came to the conclusion and Dawn confirmed it and agreed with me, it was main curcuit board wich was almost $300... But it was the problem. You cant go wrong when u can return the part if its not it, other places dont refund your money especially on electronic components.. I hope this information helps resolve someones problem..Im no professional at this but it felt good to fix it after to supposedly 3 techs came by and couldnt figure it out, all they said that it was a very nice fridge. Its easier to fix the problem on mine than replacing the whole unit, its a custom unit with custom cabinetry.. dont give up.. Thanks to Dawn and appliance parts pros!