ok so i bought a 1988 cadillac sedan deville from my wifes father. and well long story short

the climate control is acting funky ... so weather its ac or heater it only blows out the bottom vents. theres a trickle of air out the defroster vents and absolutely nothing for the dash vents ( which is what i want) i went and replaced the climate control module hoping it had just got twisted and old in there but to no prevail. no matter if its on eco or auto high/low it all acts the same. i have no diagram to even begin to look inside the mess of cables in the engine for a vacuum leak and i can not hear one. someone has told me it could be a controler arm for the climate control and if so is there a way to open it .. its driving me insane and i dont want to drop money into my cadi like that. shes got 230k miles and is in pretty good shape in my opinion for the time its had on the road. at this point thers so many little problems here and there im not really looking to repair and run as a daily driver other then work and back but regardless of that she gets me to work and back very comfortably and spacious .. as well as quickly =P

any advice would be appreciated. cause i am stumped =(