After watching the videos on what could be wrong, I purchased the heater assembly, thermostat and the defrost timer. The problem was the heater assembly, but while I had the thing apart I thought it best to replace all. The assembly and disassembly was more involved than what was shown on the video. I needed to remove both side rails to be able to remove the access panel. It was obvious that the heater was bad. Actually replacing the assembly was quite simple. I had difficulty locating the thermostat. I was able to remove and replace it without removing the entire ice maker which was done carefully and with small hands. Water leaks onto the floor when I use the cold water or auto ice maker. I'm not sure where it is leaking so I will just leave the water shut off. An earlier repair I changed the valve, there is a second valve further in which is too difficult to access so I will go old school and fill the ice bin with ice from trays and a pitcher to filter the water. I am glad I had a spare freezer to keep things cold until the repair was finished. The refrigerator is cleaner now than it has ever been!