This just started and it's very, very annoying! I'm hoping its not too big of a deal, but since it's HVAC it probably is

The only place any air will come out is the main face vents no matter what I change the control to. It just keeps coming out of them unless I turn it off!! Any advice on where to start??

 

I think those controls run on a vaccum sounds like you have a leak somewhere and the
valves are not pulling to close doors to direct it elswhere..

 

there will be a small black hose plastic hose about half the diameter of a pencil coming out of the firewall, connecting to the purge solenoid. Thats the hose that controls where the air comes from. Check that for cracks or kinks.

 

your blend doors are probably broken. my ricirc door broke over the summer. replaced it my self and a week later the blend door for the floor broke so now it only comes out the defrost vents