Did you check your batteries, to make sure the connections are good and tight? And they are secure? Sounds like a ground somewhere in your light system? Good time to go thru and check them all, wiggle some wire's, and see if you can recreate the light's going off and on! It might just be a bad or weak light switch!
Back in my Trucking days, we had old KW cabovers that this would happen to regular enough, that we always had extra road lights on a different circuit that we could turn on if needed! Rail!
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Retired, and "Always on Holiday!"
1996 Monaco Windsor 38PB, "Mona" 275 HP., 8.3 Cummins, 3060 Allison 6 speed, 2001 PT Cruiser, "Bailey"