I actually found a helpful video on YouTube the went through the cooling system and it indicated that if you fridge was not staying cool and I had excessive amounts of ice on the freezer side I believe they called in the evaporator. That 9 times out of 10 it would be the Defrost heater as it would not be engaging and melting off the system. I did test my unit and it was not functioning. I was able to order my part and within a few days it was good to go. the part I received was a double heater and i had a single unit in mine, but the instructions where great and easy to follow!