For some reason only 1 side of my trailer lights are working. All worked a few days before now only 1 side. Tail lights and blinkers are good but when the lights are on only the left tail works. Preliminary inspection and I cannot see anything that just screams at me. All wiring is "clamped" to the trailer and I haven't enough day light to really pull it all off. Any suggestions before I really dig in? I checked with both of my trucks and it is the same with both so it's not a vehicle issue.