I did a search and found the opposite problem, but not my own. Just today, my HVAC in my 2013 F150 suddenly decided to automatically start switching from the fresh air setting to recirculate after a few minutes of driving. It does not illuminate the recirculate button on the controller, and I can't switch it back once it changes. If I shut off the truck and restart it, it returns to the correct configuration for another few minutes before it arbitrarily just changes to recirculate again. I'm not familiar with how this system works in these trucks, if it's vacuum based like a lot of vehicles or if it uses electric servos instead. Anyone have any ideas?

 

 

If you are Forscan capable, I believe there is a test in Forscan for the AC system that MAY point out a problem or your problem. In "auto mode" this system is suppose to select best operation for the current demand.

I think there is also a Ford diagnostic mode you can enter, via a key combo and button while turning the key on. Sorry I cant remember what it is right now.

 

Thanks for the responses. I don't have any capability to scan this function, but I also don't have automatic temperature controls. Just the manual dial. It would pretty much have to be something in the electronic controls if the system doesn't rely on vacuum pressure or something to hold the fresh air door open, as is often the case with other mechanical functions in HVAC systems I've seen before. I'll try disconnecting the battery and see if it goes away.

 

The controls are still one piece electronic from what I understand, in all versions of HVAC for these years. Forscan is a computer program that would allow you to scan regardless of what features you have. There is a sticky thread at the top about Forscan.