My foot is on fire.

[ceejay]

I have no idea what's up with my floor vents. Ever since I got the truck, heat has worked, and when I put it on defrost, the floor vent shuts and I get defrost like it should normally work. My problem is when it's not on defrost, that flap is wide open on the bottom and my foot gets HOT. When I'm on the highway, it's bad. Of course city driving it's not bad, because it's just engine heat blowing through. So what is letting the heat through?

 

[gmbellew]

air comes in the floor vents be design I think to ensure the fumes don't overtake you. you should be able to slide the temp to cold and the air won't flow across the heater core.