Currently my Frigidaire will hold 36 degrees on the fresh side most of the time and 0 on the frozen side about half the time. The rest of the time the frozen side hovers around 20. When the temperature is high the coils are evenly frosted with thick frost and some build up. Then all of the sudden it will defrost and it will be fine.

So far I have replaced the defrost thermostat and the main control board (though I used the existing harness). The unit will definitely defrost as I have seen the heating element on and the frost will clear and the it will definitely hold temperature for extended periods.

Typically, the high freezer temps will occur after loading the fridge or opening it multiple times. The temperature will rise and usually stay that way for around a day before coming back down. That said, when it is working properly it can drop from 20 to 0 in a few minutes.

I am not sure what to try next so thanks for any help!