I wouldent drill a hole. I mean if there is a hole to let moisture out, then it can surely get in. It just wouldent build up like yall have mentioned. I have had this problem before and quickly came to the conclusion that it wasent cracked and was because of the rubber seal. Those seals dry up, plain and simple. Because its so easy to remove the tail lights on these cars its a good idea to keep up with those seals like regular maint. Simply said, that rubber drys up, and doesent seal like it did 10 or so years ago. Simple fix: take all of those gasket/seals off, take some vaseline and rub it all over those bad boys, then put them back on. It would be wise to remove the condensation in the housing with compressed air or a rag and screwdriver before putting it back together. The rubber will in a sense absorb the vaseline and swell up, once again sealing like they should. Ive done it and never had a problem after. Sorry for the long post, just wanted to be clear. Good luck on whatever path you take.