I can't change where the blows form

Question edited for clarity.
Question moved from Home Heating and Cooling.
.
What is the difference between Pontiac Grand Am and Grand Prix?

The main difference between the Grand Prix and Grand Am is that the Grand Prix has a plain body and automobile AC system. On the other hand, Gand am is a curved-bodied and manual AC featured vehicle. Both the automobiles have amazing features and are different from each other in several aspects.

The parts you mentioned should be fine.

https://www.google.com/search?q=2000+Pontiac+Grand+Prix+v+1996+Pontiac+Grand+AM

..

Broken/disconnected cable or bad actuator assuming all fuses are fine.

On this website (link below) you find fuse box diagram and description for Pontiac Grand Prix 2000

Pontiac Grand Prix mk6 Sixth Generation 2000 fuse box diagram Auto Genius

It's most likely a vacuum line, look under your hood (close to the cowl panel) for a disconnected, cracked or broken vacuum line.

In some rear cases, it could be the vacuum switch (in dash). Or vacuum diaphragm (under dash).

Hope this helps you ???

It soounds like some of the ducting came loose, maybe under the dash. maybe elsewhere.
Check the connections on the back of the air control section.

Ac hose leak?
leaking heater core?

Hint: it leaks when it RAINS

If it were related to the heater core or the AC drain, it would be leaking when it is not raining also, so those diagnoses are not logical.

The grand prix has a long history of floor leaks from seal failures around the air intake under the windshield cowling, where RAIN water runs in.

you probably have a vaccum leak.check all the hoses for a vaccum leak under the hood around the engine.

It is most likely a temp door actuator motor in the dash,the dash will have to be removed to access it.

You would need to buy a factory service manual for that blend door diagram. Try eBay for a used manual set.

linkage inside dash or relay for electric front vents went bad
linkage sometimes comes off its holder from usage this is normal there only held in by a upin under the dash
if electric the relay for the the top vents needs replacing this i believe will be with rest of the relays in engine compartment