Thanks for the advice. I'll see what I can do.

Maybe that is true about the center vents. I simply closed them and the car gets warm inside much faster, and the windows don't fog as quickly either. I think I'll keep it that way for now. Maybe there's actually no real problem. It just seems colder in the car than in the past winters I've had it.

I have limited space, so I can't do a lot of work myself, and I'd like not to sink a couple grand into whatever this issue is. The car is quite nice otherwise, I can deal with this hopefully temporary glitch.