I did a search on this and came up short. My driver's side (stock) fog light had moisture in it when it rained, washing, etc. and was blowing bulbs as one would expect.

Got a nice used replacement set off of e-Bay... then wondered if the glass on the old one could be re-sealed. So I carefully pulled the lens off using a screw-driver, lightly sanded the flange on the lens, and scraped the inset on the shell and am now going to try to re-seal the lens to the shell using high-temp epoxy and top it off with some black silicone (Permatex).

Has anyone else gone through the trouble of doing this? I'll post my results for those who might be interested.

 

If that was where it was leaking from you should be fine. Making sure the inside is completely dry and that the connections aren't rusted would be the only other thing i can think of.