A c/ heater climate control Pontiac Grand Am 04?

[funkyman20002000]

im looking at a really good used car but the only problem is it won't let me change where the air comes out, meaning to blow he air on me or my feet or both or to turn on the defroster. he knob spins all around in a full circle and it wont change the settings. I was wondering

1. What can be wrong with it not changing
2. How much would it cost to fix it in a shop vs getting parts so i can do it myself?

 

[Zimgxp]

Could be the knob is just stripped. Pull it off and check where the shaft goes.