Not blowing out

[T.slabseeker]

When I switch my a/c on it does not blow out the unit under the dash. Does everyone know what I need to look for to be the problem. Thanks

 

[RedFish]

there's a bunch of vacuum operated servos that move the doors directing the air flow to different places. The push button controllers found in before 73 models were more problematic but the later with 2 sliding levers can fail too.
I would start with a factory service manual and follow that test procedure. Maybe you'll find it simply a broken vacuum tubing. Good luck