Hello

1995 chev grumman step van.

My running lights on the roof (5 orange front, 5 red rear) aren't working?!
All other lights work.
Maybe a bulb, but would that turn all others off?
They did work, passed a safety in November 2010.
Answer could be from any or other vehicle, and I'm not seeing it?

Any ideas or clues?????

Thanks in advance!

Greg