If the compressor and fans are operating for long periods of time, the evaporator would need to be checked. If it is not blocked up with ice, it is very likely that there is very little frost on any of the evaporator coils. This would commonly indicate a sealed system issue. With this in mind, inspecting the evaporator coils would be recommended.

Having a similar issue. The freezer is not reaching the 0 degrees or lower and its between 20-40 degrees. The same is for the refrigerator, but it is much closer to the 36 degrees reaching between 40-45. All the fans are running... The refrigerator fan, freezer main fan, freezer ice maker fan, fresh foods fan and compressor fan.... they are all working. I tested the the all the Thermistors by going into the Diagnostic Mode and running the series of commands and they all appeared to be reading the correct temperatures.