We recently went away for a month, and left our Amana fridge/freezer running. When re returned, the fridge compartment was near-freezing (milk on top shelf ices up, nothing on the lower shelves freeze), and our freezer was filled with frost and ice. We defrosted the entire thing, and left it for a week, making sure that the door was securely sealed. Its started icing up again, and the milk is freezing again.

So, I took the back off the freezer compartment, and the controls from the fridge which is where the defrost timer is located. I had to cut one wire that led to the defrost thermostat, and tested it. When it is frozen, it has continuity, and when warmed up, it doesn't. In other words, it works fine. I checked the resistance of the defrost heater. It ohms out at 35 ohms (correct) and works fine. I also tested the defrost timer, by marking where it was with a Sharpie, and letting it advance. It advances as it should, hitting the defrost setting on the timer every 6 hours.

So... what else could it be? I'm wondering if the freezer thermostat is bad, or if there even is one. Is there a way to test the thermostat in the freezer control knob? No matter what I set it to, including off, it still runs the compressor full time.

The fans are working fine, as is the damper. I pulled the freezer control thermostat out, and its dead. Even in the off position, there's continuity between the switched pins.

If I'm correct, the freezer has been running constantly (except when the its in defrost mode) and even though the fridge damper is mostly closed (setting of 1), the air from the freezer is cold enough to freeze the fridge.

So, $38+s/h, and I'll know for sure.