check the ground wires behind each headlight bucket
Daily Driven: 1985 CJ7 Renegade, 258ci 4.2L (TeamRushed and Nuttered), T176/Dana 300 (in need of an overhaul), Weber 38 DGES, Ion Alloy 174 15x8, MasterCraft Courser MT 33x12.5x15, Front Axle Dana 30 w/ Superwinch Hubs, Rear Axle AMC 20 w/ one piece Alloy USA.
Mine did that the other night. I checked everything--fuses, grounds, connections and couldn't find anything. I hadn't driven it in a while. I stepped on the dimmer switch on the floor board and they started working. I guess with the humidity and not being used for a while, there may have been a little corrosion on the contact. They work fine now. I hope that your issue is an easy fix like that.
I've had the same issues on a VW Karmann Ghia, and the workaround was always to toggle the dimmer switch to high beams and back. Not entirely sure what causes it, though. Old worn switch contacts maybe? The VW has all original switches and relays, while the ones in dad's Thing (which has never had that issue) have all been replaced at least once before.
How old is your dimmer switch and headlight switch? Somehow this doesn't feel like a main switch problem, but a dimmer one.
Not sure but it looks good looks new the dimmer that is I took it apart everything seems good the headlight switch looks a little old .is there a way to test them, or is there a relay on the fuse box I should check don't wanna replace stuff that works