Air direction doesn’t change with dial

What is your question?

My air flow direction doesn’t change in my 08 Jetta (manual controls). It just blows at my face and won’t rotate to the defog or feet. I do hear a clicking when turning the dial but nothing happens. It does blow hot and cold fine. Is this the blend door? I had an aftermarket stereo installed right after I bought the car, somebody suggested something in the hvac might have gotten loose by that but I’m not sure what specifics to look for. Mechanic is quoting almost 900 to diagnose and repair.