[A/S] Wiring, Lights, Rear bath... Help?

[suburbanbloom@xxxxxxxxx]

I am hoping someone can help...I have a 1976 International Land 
Yacht, with rear bath.  All lights were working fine, I thought.  All 
of a 
sudden the  bath lights, (original), the ones on each side of the 
mirror quit working.  Everything else is okay. Thinking, six bulbs 
could not blow at once, I replaced them anyway.  No luck.  I have no 
clue where to begin to solve the problem. Any ideas what it might 
be?