I have a 2005 Ford F-250 6.0 liter diesel. I recently tried to turn the A/C on here during our nice California summer. While the A/C did come on and got cold, it wouldn't blow out of the console. It was stuck on the defroster. I tried turning the **** to other settings (floor, floor and console, etc.) and still it wouldn't change. Are these still controlled by vaccum? Any help or suggestions would be appreciated. Thanks!

 

I have the exact same problem with my 1995 F250. I have read in another post, don't remember which one, that the system defaults to defroster if the selector system is not working. Under my dash, there is a vacuum control. If I zip tie that to keep the arm in then the dash blower will work. I can not determine if it is the vacuum control or the switch that is not working. Good luck with yours and please let me know if you figure it out.

 

Fixed it! Turned out to be the vacuum pump went bad. Unfortunately if you get a dealer part it will cost you about $250!!! If you go down to your local Napa dealer they can get you the pump for about $90 (check local listings). The vacuum pump controls the A/C changer as well as the foot pedal adjustments. FYI.

 

That is good news. I have gotten real tired of zip tieing the vacuum control unit under the dash to get the blower to come out of the dash.
I guess the pump would make sense because it is common to the blower control and the vent control which is also not working in my truck. I did some continuity checks on the selector switch and found nothing wrong, and then chased as much of the vacuum line as possible and replaced a lot of that (mostly under the hood) because of dry rot. I think the thought of the pump was avoided because of cost and effort.
One question though; I guess I can tell if the pump is working or not without taking it off the engine? Maybe I can just disconnect a line or two to tell if it is actually pumping?