Dunno about temp selection switch. AC works as it should. Had it set to 69 today and it kept things about how they always are. I tried turning the passenger controls on and it doesn't make a difference.

I've seen the blend door mentioned before, but no one has described what I'd actually be looking at. I've worked on lots of cars over the years, but never did much with the HVAC, becuase I've never had an issue, other than changing a few heater cores.