High Beams/Low Beams

[BeeX4@domain.elided]

I saw a post about this and it made me think of a problem I have had for about
6-8 years now, it obviously is not a big deal but...
Sometimes my low beams don't work.  I have rewired the truck a couple of times
due to weird problems after the first time.  I replaced the floor switch and
the lows worked fine, for awhile.  The the lights went through a period of not
working at all, now its just the lows again.  I have checked the floor switch
for continuity and its fine.  I can't find any breaks in the wire, nothing
piched or green or anything.  Is there a ground I am missing?  

Brian
'65 D1200 4x4 345 4bbl 4.11 the "Taxi"