all of sudden my air flow stop on windshield glass on 1998 Chevrolet Venture

all of sudden my air flow stop on windshield glass so i can't drive in rain. if i block (close)all vent then i get very low air flow in windshield. how can i fix it

by in Elmhurst, NY on March 20, 2013
2 answers 2 comments
ANSWER by on March 21, 2013
Check for any broken vacume lines that supply vacume to HVAC controls. Vacume is supplied from engine intake manifold.
COMMENT by on March 21, 2013
thanks a lot
ANSWER by on March 21, 2013
Sounds like selector switch not switching, will it switch from vent to floor and back? Anything fallen into defrost vent? Check ebay for control panel at a good price, if needed. No vacuum defalt should be defrost!
COMMENT by on March 21, 2013
thanks a lot