The A/C in my '93 coupe only blows out the floor and the defroster no matter what adjustments I turn the dials. When I bought the car it was like this so it is not a new problem. Where do I start to look?

Thanks in advance.

 

check the vaccum line that goes through the firewall and make sure it's not broken out under the hood.........also it could be disconnected behind the control panel