My dirver side fog light was half full of water. I got under it and noticed a tube connected to a plastic nipple. I pulled the tube and got a face full of nasty water.The tube was plugged with some dirt and grit. Is that tube to vent condensation? How does so much water get in there? No problem on the passenger side. (2000 Disco II)

 

You may have a bad seal around the lens allowing water in, kind of common, just keep the tube clear and you'll be OK.
Mike