ac quits blowing out vent and switches to defrost vents???? help

[duckett]

i am puzzled, my 2002 explorer from time to time the air blowing out my vents the ones aimed your face will periodically die out but you can still hear ac blowing so when you put hand on dash and its automatically switches to defrost vents than switches back ??? its still cold and got power but somehow switches to defrost vent for appx 8 to 15 sec than switches back everything works fine, i cant find any vacuum leak and the flapper in dash seems to do whats its supposed to. it seems to occur more at higher acceleration. any help knowledge or solutions would be great thanks!!

 

[buckwill]

my 2000 lumina did exactly same thing, heater or ac would die off or divert,, i cud hear blower running but no air from vent,, old timer,, well older than me sed to look to vac supply from engine, i eventually found cracked vac line,, can be most anyplace but most likely before,, twen vac switch in dash and engine u will find your problem, let us know when u find problem, buck

 

[eddie baller]

i have the same problem in mine