Initially, I found a block of ice (since melted away with a hair dryer) around the area of the freezer thermostat. (see picture)

I have replaced the control board, the freezer thermistor, and the defrost thermostat. I have cleaned the condenser coils, the drain connection, and performed the tests using the controller test protocol (at least those that I have been able to find). I measured the defrost heater at about 31 ohms, and tested with my finger (burned) during manual defrost. I also measured the refrigerator thermistor and it appeared to be correctly tracking. The evaporator was not heavily frosted over (see picture). There is no change in the way it is operating, still too cold (ice cream is rock hard). The fresh food section is at about 37F.

It passed the following tests:
1. Defrost Thermostat Diagnostics
2. Refrigerator Compressor & Condenser Fan Diagnostics
3. Freezer Evaporator Fan Diagnostics
4. Refrigerator Sensor Diagnostics
5. Freezer Sensor Diagnostics
6. Refrigerator Damper Door Diagnostics

I am completely frustrated with this issue. The refrigerator is only about 2.5 years old.

Thanks for any ideas on this.

Rick

I found the problem. I initially replaced the freezer thermistor, when that didn't work I replaced the controller board, still didn't work. I found the pinout for the controller chip and measured the resistance of the freezer and fresh food thermistor from the board connectors. The fresh food thermistor measured ok, around 10k-11k at room temp. but the freezer thermistor (the one that I had replaced) was way too low so the (new) controller thought that the freezer was always too warm, making it way too cold. I reinstalled the original freezer thermistor and it worked like a champ! The original problem was caused by the controller board. The replacement freezer thermistor was a red herring (either defective or they sold me the wrong part).