AC doesn't work. Had to change compressor and evaporator. What else?

[Eastbird]

So I have a friend of mine who has 2010 ford explorer V8. He has a problem that the AC doesn't work. He took it to a mechanic who requested changing the evaporator, then compressor and still not working. However, the AC works sometimes while driving and turns off by itself. One mechanic guesses that the problem could be from the controllers, but he isn't sure. The controllers in this vehicle are all electronics.

Any ideas of what the problem is.