In a nutshell: I have a '00 Integra, and my passenger side taillight takes in water when it rains.

It just rained, and there's some water inside the lens assembly. This is the third factory lens assembly I've had put in (fortunately all for free so far, though retail on them is nearly $300) within a year and a half for the same problem. I don't think they'll give it to me for free anymore (apparently not under warranty), so does anybody know how I can fix it myself? Would appreciate help, thanks!

 

Check the tailight gasket, I had a similar problem.

 

Just take off the tailight and wipe down the dirt from the gasket, worked for me.