I have a 05 F250 and encounter the same problem with the AC always on. Took it to the Ford dealer and the said it is always on in all positions except either the upper vents or the lower vents only, not both. This is crazy. I always keep mine on both upper and lower vents all the time. The manual does not say anthing about it being in the AC postion all the time. The dial give you no clues at all. If that is so, what is the "AC" setting for???? Isn't it the same as the upper and lower vents on AC all the time??? The manual even contradicts itself and says to put the switch on AC and upper vents at the same time to clear the side window of fog/frost. Well this is impossible since the two setting are on the same dial in complete opposit positions. There are 7 settings on my dial and only the 2 setting are not AC settings. I have had plenty of cars in my life and everyone of them allow you to have fresh air only comming in thru the upper and lower vents without having the AC compressor on. Who was the idoit that designed the climate control on the Fords??? How come they don't just mark the climate control switches correctly to know when you are using the AC and when you are not? It that too complicated??? Frustrating... I've been pulling a 5th wheel all around the country for the past few years with the AC on and not realizing it. What a waste of power and gas... I would bet that more than half the F series owners don't realize the AC is on most all the time... Anybody else think this is stupid??
Sorry for the rant..
Steve | 
