Drilling Hole in tail light to drain water

Phbbtt!

I don't remember just how old my Accord was when I drilled a tiny drain hole at the bottom of the lens assembly and applied duct tape above to keep the water from flowing down there, but it worked. The lens remained dry until I disposed of the car when it was 23 years old. Then a couple years later the car reappeared six blocks away, and stayed there until it was over 30 years old. As that kid was packing up to move away, that lens was still dry.

Other situations might not be as amenable to this solution. But in my case, it worked, with materials already at hand. And it held.