Which AC system do you have? Turnable dials or the electronic controller? If it is the turnable style, blend door most likely. Electronic can be the controller head, or blend door.
Check by turning the dial and listening for the vac to switch. If you don't hear it or do and it doesn't change, blend door most likely broken at the mount point. If electronic, try the different outlets. If no sound, check the vac pods for vac. You can open the glove box and see into the area. You'll have to pop the box out of the top holder, but it bends easily to allow access. You may have to check your service manual for the exact way to check the electronic controller. It's fairly straight forward, but can consume a lot of time if you have to cut and modify your dash. Longer if you remove the entire dash assembly. There are several writes up on here about the blend door replacement. Type in
"blend door" in the search forum. You'll find enough reading to keep you busy for a while. Good luck