I had the same problem. Before you go drilling check to make sure that the rubber seal that goes around the base of the lightbulb socket is there. Those little suckers like to stick to the body of the corner lens, so when you pull the lightbulb out of the original corner lens the seal will stay with the lens instead of with the bulb. It happened to me, when I changed my lens, thank God I didn't throw out the original lens, so the seal was still on there stuck. After putting the seal in its right place I haven't had any water in my lens.
