Fridge and Freezer are Warm Ice is still being made

Hi - I just had the same problem on a 48 Monogram 1996 model.
The guys at the factory told my local service center that it was the main logic board ($200 for parts) and they replaced it, but that wasn't it.
It was the evaporator sensor. i don't claim to understand it all, but I think that the sensor is responsible for telling a heating element to turn on and defrost. If it does not do it's job, then frost builds up (You can feel the frost if you feel up in the freezer, up hight and in the front)) The frost keeps the cold air from getting to the fridge. Eventually the logic unit will freak out because ti is trying to keep the fridge cold, but the fridge send back that it is hot.
The repair guy may not want to replace the sensor because it is like an hour and half to get back in there. And it is a tight fit.

Check your coil. To do this on the back of the unit you should see a panel and some screws to remove. Remove those screws and look for a thin layer of Frost not ICE on the coil. If there is not frost on the coil the compressor is bad. If there is frost or to much check the fun and the thermostat