This is my first post, I hope I'm putting it in the correct spot.
Here is my initial problem. In my 2000 Pontiac Grand Prix GTP Daytona 500, there is dual climate control (automatic/digital) and on the passenger side the AC blows nice cold frigid air but the driver's side blows luke warm/ cool air at best. So I did some research and discovered that I may have a bad blend door actuator. I got a replacement actuator but when I finally got the thing removed I found that the original actuator was functioning just fine. So I figured that it must be the blend door itself. When I reached up into the tight spot to turn the knob controlling the blend door it was very stiff. Initially it seemed pretty well stuck in a vertical position. After freeing up the knob I was able to get about an eighth of a turn before I encountered a bit of resistance again. Watching my actuator turn I see that it takes about a quarter of a turn to get from the digital setting of 60F to 90F. To complete the rest of the turn is very difficult, actually impossible to fully complete the turn by my calculation (sight). After calling the GM dealership they told me that HVAC distribution box may need to be changed, "over time the distribution box may become warped and cause the blend door to rub against it" causing the aforementioned and unwanted resistance.
Where is the HVAC distribution box? Is it extremely difficult to replace? Any pictures or diagrams would be helpful.
Could there be any other explanation or possible fixes?