This was my first information post and I think it's cool that there is so much interest! i drove in 0 temp yesterday just because I'm bored out of my mind recouping from surgery, What I found is, way more heat in the cabin on vent with fan on low. It actually cooked me out. My left foot got a bit cold. Now if I went to heat I had to put blower on 3/4 just fo stay mildly warm. I hear all the flappers working but can't even tell you where the (heat) is coming from. Vent good, heat bad, defrost fair.
( Create a team, analyze, make a plan, then ask the wife if it's OK.)