Late model Blend door????
 

I have a 94 and a 96 Cadillac Fleetwood. Both do not have the best air conditioning, and the heater blows through the defroster and the floors, but not the main vents. Ive had this problem before on a Lincoln Towncar. It was called a blend door actuator on them, and I had ran a code test on the eatc. Can this be done on a Fleetwood, how can I run the test with the climate control??? Thanks guys