Ford - Taurus :: 2005 - Intermittent Loss Of AC Cooling

2005 Taurus - 6cyl - 3L - 85K. 2nd post on this on. Have had this vehicle to 2 mechanics now and problem is still there. First mechanic checked the refrigerant pressures, added dye, couldn't find a leak. Told me that he had to add a small amount of R134 and the pressures were "spot on" but the problem was still happenning so he supposedly trouble-shot the system and found it to be electrical. He said that the controls on the dash were causing the problem and changed them. When I picked it up, everything worked fine for the first day. After that, the same thing happenned where it would intermittently work.

I took it back to another mechanic (who specializes in AC work) and he evacuated and recharged the system (also said that he added dye and couldn't find any leaks). When I questioned this, he said the pressures were low and that would cause the intermittent loss of the AC cooling. This time, it work for 2 days and then the same thing happened where it intermittently works. There is no pattern at all to it working. Sometimes it's when the car is first started ; sometimes it quits just driving down the highway ; and sometimes it quits for 5 minutes and then just comes back blowing ice cold air. I suggested the AC compressor clutch or coil to the 2nd mechanic and I'm not sure he even checked it. Does this "still" sound like a leak somewhere or more electrical ?