My A/C works on my 93 Bonneville but I do not get good airflow from my vents. When I place the climate control switch to A/C Max, the blower motor changes to a faster speed but no additional air flows from the vents. I'm assuming a damper is not closing or opening when it'* supposed to. Vacuum lines are connected. What and where can I check? What is the best way to get to the dampers?
There was a previous thread on this but the links no longer work.

Try giving this a try. YOur year will more then likely be a bit different, but this should give you a good place to start.

https://www.gmforum.com/t278997/

Thanks for the detailed instructions and photos! Even someone as mechanically inept as myself should be able accomplish this.

Let us know how it went. If I need to make any changes to the write up just let me know.