RE: AC blowing out defrost vents..
Check for a loose vacuum line/cluster plugunder the dash on the passenger side. Sometimes a passenger foot gets under there and catched the vacuum cluster. Also check the black vacuum line that goes to the vacuum canister between the inner and outer fenders. The line will sometimes get chaffed thru by vibration where ot passes thru the inner fender.
2016 Ford Fusion SE (1.5L Ecoboost)
2015 Ford F-150 Lariat Supercrew (3.5L Ecoboost)
2010 Lincoln MKZ (3.5L DOHC)
2007 Ford Focus SE (2.0L DOHC) A.K.A. "Zippy"
2004 Ford Freestar Limited (4.2L OHV)
Generac 17.5KW Generator (33HP Twin Cylinder)
Farm Hand 60 Gallon Compressor (3 Cylinder)
AMSOIL in everything I own that I can get it in...
"Have a good day, and a better one tomorrow"