I've has this problem for years, the headlights kept filling with condensation. I finally drilled a small hole in the bottom of the plastic light. I drove for about 2 hours in pouring rain and they still work fine. When it dried up, so did the lights, theyr'e finally back to being all clear like stock, not yellow and foggy like they use to be.

 

thanks for that, my lights get foggy to so i might have to try that

 

I had that problem a while back. Click and clack did an article on it. They said that the plastic lenses develop small cracks in them and the water penetrates that way. You have the right fix idea.