Front air conditioning

the second answer probably fixed it..just been 14 months,but they never replied back with if it fixed it or not,but lots never do, although it would be very helpful to others with the same/similar problem..i have a ford..it's a 2000 F150 and anytime i hear "blowing out the defroster"and or floor only,then most of the time it's a vacuum leak under the hood,pass side firewall,the harder/smaller lines somewhere around that tee maybe from acid from the battery or just got like me"OLD" then the blower defaults to the defrost mode until repaired...vacuum hose/fittings are cheap...