I live in south florida so I never have to use my heat or defrost. However since I have owned my TL ( bought it 2 years ago), I have always had the windshield fog up a little by the defroster when I have my AC on LO for an extended period of time, and I only leave it on the main vents,never change it. I have looked everywhere and cant find any info about this. If anyone has had a similar problem any info would be appreciated. I dont know if this is something normal or if its a blender or something that needs to be replaced

 

do you have it on fresh air or recirc?

 

Guessing it's simply the cold air blowing on the windshield and the warm humid South Florida air condensing.

 

Mine does that too if it's humid out. It's normal.