PROPERLY adjusted foglights are counter productive on a clear night and are
HARMING your distance night vision by making your near field too bright....
as is blazing your dash board lights at full brightness.  Properly aim your
headlights, power your headlights through a relay, and dim your dashboard
lights and you won't have and you won't need or want your fog lights on
clear nights.

Fog lights owners and buyers should read:
http://www.danielsternlighting.com/tech/lights/fog_lamps/fog_lamps.html

As a side note if you have a VW factory fog light switch, you'll notice that
you can drive with your headlights off and your fog lights and parking
lights only on.  Fantastic in heavy fog or snow.

Also good reading for everyone for correctly aiming headlights and fog
lights (at the bottom of the page)
http://www.danielsternlighting.com/tech/aim/aim.html

Finally, proper foglights are mounted below the bumper.    Less than ideal
for protecting your fog lights, but proper for them being most effective.
That said... I have PZ fog lights on my van.  They are less than ideal, but
they certianlly work.   I absoultly love them for driving dirt roads at
night, really great in campgrounds at night too.  I would absolutely never
drive with them turned on on a clear night.

-Jon