Ford Repair: 98 Ford WIndstar airconditioning, ford windstar, vacuum leak

Question
The air conditioning in our van only blows on the windshield.  It blows cold, but won't blow through the dash vents.  I've been told that there is a vacuum leak somewhere preventing the mechanism that directs the flow of air from moving.  How do I find this leak if that's the problem?  Is it?  Also, there has been a longer lasting problem with the rear climate control.  I don't know if they are a related problem or not, but it doesn't cool at all, it only puts out heat, so it stays off except in the winter.  I'm am mainly concerned with the front air problem though.  The van has approximately 190,000 miles on it, so I know it's going to have problems, but this is really the only one that is an issue now.

Answer
as far as the vacuum leak you need to look around the rear of the engine near the firewall (panel between engine and inside) look for your a/c and heater hoses around one of them will be a vacuum hose probably black skinny plastic-follow this hose back toward the engine
there should be a connection to another hose unplug this and with the engine running see if the hose on engine side has vacuum if it does problem is probably inside van-if not follow that hose to see where it goes make sure it is not broke/melted/pinched etc if it connects to another hose or canister follow the hose leading from it. if you have rear air contrl head in dash cold be and leaking vacuum have seen several.

as far as heat only probably bad blend door actuator or broken blend door-could get expensive if so  

good luck!