Just replaced lites on trailer, everything works fine till I turn on the headlights then nothing works - I have a checker and it shows everything is o.k.
Expert Reply:
It sounds like you have a bad ground connection. If all ground connections are not making good contact to bare metal, when the taillights are turned on, the increased amperage draw will make this problem show up.
You will need to check all of the ground connections especially where the taillights are mounted to the trailer frame, and where the light brackets are mounted if they are bolted to the frame. If a plastic license plate holder is mounted between the left side taillight and the trailer frame this could be the problem.
Once you have all of ground connections checked, if the problem persists, you will need to check for a broken pinched or frayed wire on the trailer somewhere.
expert reply by: Bob G
