This topic was covered in the tech forum a few months back. From what I remember, the cure was to leave the lights on for a short while and the reason for the moisture is as you stated. The lights are vented. I wouldn't expect that to happen but it does. I'm glad we don't get much rain here. Seeing them fogged up everytime it rained would tick me off. Oh, there were a couple of folks early on that got their dealer to swap them out... I think that was before the TSB. Good luck .