Two years ago my Defrost Heater went bad in this frig and thanks to appliancepartspro.com I was able to replace myself. Back then, while I was troubleshooting and waiting for parts, when I dryed it with a hair dryer, it was good for another couple of days. Now I am having the same issue but when I dry it with a heat gun(moving it fast, not too hot), it covers back with frost within a few minutes. Do that sound like it would be the defrost heater again? That's awful fast for coils to ice over. The defrost heater shows no sign of working. It's not turning red. So it may be bad but it seems like if I put in a new one, it would stay on constantly since the coils are freezing constantly. Could it be a thermostat or temp sensor as well? I received a temp sensor when I last ordered and I still have it if needed. Since I don't have an ohm meter to test parts, I guess I'm asking for a best guess to see what you folks think. We came home from vacation today and it was like this, and according to the pet sitter, it was find yesterday because her little boy was getting ice cream from the freezer. It's also possible the little boy could have left the door cracked open. Not sure if that would cause this issue or not. Any ideas would be appreciated. Thanks!