This is a follow up to Freaking Fridge
The Sears repair guy was by promptly at 8:00 AM today and replaced the defective fan in about 15 minutes. No charge.
This is the fan that sits by the interior coils and recirculates air in the fridge. The replacement fan that I received on the 21st had a new and improved feature to increase efficiency: an internal thermostat that doesn't let it go on until it's below a certain temperature. This thermostat is in series with the temperature control thermostat. My old fan went on whenever the temperature control thermostat click on, without waiting for the freezer coils to get cold.
There's good reason to believe that it was the thermostat that failed in the new fan. The service guy replaced with an old style, without internal thermostat, fan.