If your A/C on your 2012 Fusion is blowing hot, try this. When you turn your A/C on and set to cold, if the Compressor clutch is turning, if the refrigerant lines are cold yet warm or even hot air is blowing from your dash vents then it simply might be a bad contact on your TEMP DIAL. While everything else is on and running turn the temp dial SLOWLY one click at a time all the way to the right to the full warm setting then turn it back to the left again SLOWLY one click at a time to the full cool setting until cold air starts coming through. You might even stop one or two clicks short of the far left (cool) setting if you're getting cold air. If this works then you probably have a slight amount of corrosion on the full cool contact, but 95% cool is better than 100% of nothing. Also, try turning off your A/C BEFORE shutting off the car and only turn it on AFTER starting it up..
I went through several experienced mechanics and NONE had a clue of what was causing the problem. I came upon this fix myself and it didn't cost me a ton of exploratory money nor a new control head. Good luck!

 

Thanks! I like knowing 'work-arounds' like this ^^^