I hate I've had to come this far but I have spent a few days trying to search for an answer to my Ac problem. 2011 F250xlt 6.2l. Got down on her pretty hard the other day in traffic and after I left off a bit Ac went weak and has stayed that way. Now blowing through dash vents, floor, and defrost vents at same time. Switches from hot and cold fine as far as temaoture goes, but either tempature preference, same blowing issues. Had noticed lately pulling travel trailer that air would weaken a bit under high RPMs, never really thought much of it. Any setting on vent preference, floor, defrost etc, same problem. Blows through all at the same time. Had noticed that air flow has been weaker than last summer, but not too bad. But now it's insane. It's been a hot pst few weeks here in north Florida. Anyhow, pretty much isn't anything I haven't ever replaced or worked on in multiple vehiculas, but I can't find any info on this particular problem. Any help is greatly appreciated!! Thought maybe a vacuum line but not set up the same as my 6.0 was. Only see Ac and heater core lines running through firewall. No vacuum line. I'm stuck.

 

First thing I would suspect is a vacuum leak or failed check valve.

But I think your truck uses electronic actuators instead of vacuum for all the HVAC controls..

There are three or four of them under the dash, and I one of them has likely failed.

When you change HVAC settings, you may hear a click-click-click sound somewhere in the dash.

 

Can't hear any clicking sounds. But I think you're correct in it being electronic as there is no vacuum line I can see going through the firewall anywhere. Back to square 1 I guess.

 

I myself have also had the same issue of my a/c going warm briefly, it always blew ice cold even on the hottest days here in the West Texas. Now I'm stuck with just slightly cool air, so I put a set of ac freon gauges on it, I was reading 20-25psi on the low pressure but 300psi on the high pressure! If I'm not mistaken I may possibly have a valve stuck or my ac compressor is starting to come apart and caused a blockage somewhere in the system. Truck still is under warranty and will be heading to the Ford shop soon. Anyone have any other thoughts

 

It blows ice cold. Just out of all registers. Floor, dash, and defrost. Heat does the same thing. Not a compressor issue I think. Man this irritating.