Ford Repair: ac/heat selector switch, outlet hoses, ford taurus

Question
96 ford Taurus. it only works in defrost mode no matter where you turn it. will this make the ac not work

Answer
a/c will work on defrost mode but will only blow out defrost vents-if that is what is going on-check under hood for vacuum supply problem on black vacuum hose going from engine to rear firwall usually around a/c inlet and outlet hoses-their should be vacuum on this hose anytime engine is running if not probably have a bad hose or connection ex. rodent chewed/melted or just disconnected. if air is not cold when temp selector is on cold and selector switch is on defrost then you have two problems a/c inop and control bad.