Two curious things happened to me today:

1) I had an hour drive to work this morning in a cold rain (~34 degrees) after a snow overnight. As the drive wore on, the windows got foggier and foggier. I had the fan up to 4 and the heat all the way on so much that I wanted to vomit, but the windows kept getting foggier; I simply couldn't dry them out. So...I put on the a.c. thinking I'd dehydrate the air. It didn't make a dent. By the time I got to work, I was wiping the inside of the windshield with my handkerchief, and dropping the door windows to wipe them clear. A big pain -- just like my old 1963 VW.

2) Driving home, the rain had stopped, and the windows slowly got clearer. But...1/2 way home the Check Engine light came on. I took it to my local mechanic who put a generic OBD II reader on it and got a 'Evaporative Emissions, possible Leak' display (I can't remember the number). He suggested that the filler cap may have been loose; he reset the OBD II and said if the light comes on again he'd take a look; perhaps a small vacuum line had come loose or cracked.

So...are these two situations related? Might there be an engine compartment vacuum line in the HVAC system which, if split, was aspirating moisture from all the cold road spray?

Thanks in advance for your help!

Rob K.