Originally Posted by S5 SD
Headlights should be air tight!
No the A5/S5 head light is not air tight in fact there is an air vent on the back of them...the vent could be blocked and that would cause the glass to fog up. I had that problem when i stock the eropean headlights in my american A5.
2008 Black A5 3.2 Man, Gray int., Nav, Tech, Premium, 19" Y rims, (STaSiS cat back exhaust, E-Codes, 35% Tints, Badges removed, and White Fog lights and Festoons)