A bit of research on the internet indicated the most likely problem was with the defrost system. I found the service manual for the refrigerator and was able to determine that the defrost heater and thermostat passed the self test. The refrigerator would perform a forced defrost which resulted in a cold refrigerator. More research revealed that this particular refrigerator does not have a defrost timer, instead the defrost cycle is controlled via the Electronic Control board which is also referred to as the Jazz board. Some shopping revealed Appliance Parts has a competitive price AND accepts returns if the part doesn't fix the problem. I used the Appliance Parts chat area to verify my diagnosis and ordered the part.
The part arrived 2 days after ordering. Unfortunately there were no instructions, for that matter there was no documentation included. Luckily I had done further research and had an idea of how to access the Jazz PCB. The service manual had the procedure for programming the proper code for the new PCB. The Jazz PCB is in 2 pieces, but the new one came as a single piece that required breaking into the 2 pieces. This was easy enough; lay the new PCB on a hard surface with a pencil directly under the scribed break area and apply a moderate amount of pressure to break the new PCB into the proper 2 parts. Actual installation less 15 minutes plus another couple of minutes to program the refrigerator code into the new PCB. So far refrigerator is operating as expected - cold freezer + cold refrigerator.