A word of thanks to AppliancePartsPros - they delivered in one day. Ordered at 4PM CDT and received the part by noon the next day. Also, Alicia in the help department was able to locate an electrical diagram for my old freezer. This was essential for proper setup and her persistence in tracking down the diagram was top notch. Now on to my problem. One day I opened the freezer and found frost and thawing food. I attributed this to the door hitting an item in the freezer and not completely closing. This had happened before, but not as severe. We removed the food and exposed the cooling coils - completely covered with ice. After defrosting with a heat gun, I checked the defrost heater and it was OK. Reassembled the freezer, loaded the food along with some dry ice to start resetting the freezing, checked the gasket and made certain the door was closed. This worked for about a month and then the temperature began to slowly rise. Checked the cooling coils and they were again covered with ice. After reading numerous on line comments, I ordered a defrost timer. The replacement took about 20 minutes and did not require removing the food. I then examined the old timer and found that it was working, thus the timer was not the problem. Now on to the second repair - replace the defrost thermostat. This required removing the food, cutting out the old thermostat and replacing with the new one. This required an hour or so, including removing the food, shelves, etc. exposing the coils, and replacing the thermostat. Unit now works great. Thanks again the the folks at Appliance Parts Pros.