when i first got my jeep the lights would go out over a bump and then come back on after the next bump. i never intentionally fixed it but it hasnt done that since i took my dash apart to clean up some connections. im guessing it was probably a bad ground
89 Wrangler-3.5" HD BDS lift,M.O.R.E HD 5/8" booms on 35" KM2s
99 Cherokee-2 door,5" lift on 35" KM2s
04 Grand Cherokee Overland
72 Chevy Nova-in progress http://tiny.cc/BRASSBALLSOFFROAD
When mine did that it turned out to be dust in the headlight switch. I pu,led the witch and took it apart for a good cleaning. Fixed the issue
92 YJ. High Output 4.0L
Rubicon Express 4" Lift Kit, 2" Body Lift,15x8" AR 767s, 35x12.50 Xterrains, Home Made Snorkel, Sanden OBA, Home made rocker gaurds. 8.8 Rear with Discs, 4.10s F&R, ARB rear, Detroit EZ Locker front, WarnM8000 with Viking Synthetic Line, Beadlocks, Tons of Mods
My RigRater Score: 682RRv1.0 with a BOA of 13.47
I'm now doing custom bumpers and lift installs in So-cal
Lots of things could be at play here, but first start with your connections on the back of the headlights. Make sure they are clean as a whistle- including the contacts inside of the plug itself. Any sort of corrosion or rust can make a bad connection and give intermittent power.
Also double check the crimped connections on the plug too, if one is frayed then it can cause an intermittent connection. Put some die-electrical grease on the contacts to seal them up from the elements.
if you wheel your jeep alot, its not a bad idea to go around checking all your grounding wires, and giving them a good crank or two to make sure your not "wiggiling" your wires loose. Also never hurts to clean all your connections on a slow rainy day in the shop. Regular maintinence on the small stupid stuff surprisingly pays off!