Kgaleher

Thanks! Any tips on how I can fix it? (from a clueless mom

Electrical people: Im a single mom. My 14 year old and I wired his trailer. All the lights work (side, break, turning, hazards) as long as the headlights are off. Once you turn the headlights on - back lights don't work at all, side lights still work. I've grounded everything, cleaned all connections, etc. Nothing helps. Any ideas? Thanks!