AC Only Cold on Passenger Side
 

2002 Moutaineer Premier AWD

Noticed my AC was not very cold today so I added some 134a to spec with my brother in-law's help. He's a mechanic, but not for Ford. After we were done I noticed that the air coming out of the drivers side vents was warm. The passenger side and rear air are very cold. If I close off the passenger side vents, the drivers side starts pushing some cold air so I guess it's diverting from the passenger side.

Anyone know what causes this? His guess was that something is clogging the air intake cowl or there's a bad actuator that switches the vents around. He looked from under the hood but it seems clean...no leaves or anything we could see. We played with the dual control switch and it seems to work fine except the drivers side only gets hot, not cold ever. The recirculate and other HVAC controls all seem to be functional.

Any ideas would be greatly appreciated. Thanks

EDIT - Just found the link to the fresh air vent door broken, interesting, luckily I don't think I have that problem. Perhaps this like will help someone else:

http://www.denlorstools.com/autoblog...h/#comment-611

Not looking forward to ripping my dash out. Nobody else has had this problem?