ive got the hella 500 series driving lights. it has just started raining quite a bit in my area. and poof...my lights lenses are all fogged up. and it definitely has an affect on how much light they put out. do i just need to figure a way to seal them from moisture? like silicone around the mounting area? anyone else have this problem?

 

I've owned them and they all do it.
Unfortutely not much you can do they aren't a sealed beam.
Those bulbs heat up quite a bit and need a contact point to ground the bulbs to. So silconing them there won't help much.
You can try on the outside around the bezel but I think that will look like crap unless you can hide it.
I would upgrade them to something else. They are pretty much the lowest line of hella's they make.

 

Make sure the rubber grommet for your wiring is not all ripped up.

You could probibly find some sort of tape that you could stick onto the plastic housing to help seal the lense...

 

I had a set of lights that kept getting moister inside when it rained. To fix it I drilled holes in the bottom of the plastic housing for ventilation and then used black electrical tape to seal between the outside of the lens and the plastic housing. It didn't look bad, and it sort of worked, but didn't completely solve the problem.