Electrical issue

[Chamberpains]

You more than likely have a shorted wire in your marker lights. And even more likely somewhere on the trailer. Most common spots are in the tail light wiring. They rub against things and wear the insulation off till it shorts on the metal. This will also happen more in the rain and snow because the water and ice will often complete the short, then completely go away when everything thaws and dries out.

I know this problem quite well. Dealt with it just this morning in Cleveland @ 4am.

If it happens again, disconnect the trailer electric cord and see if it stays working. If so, its a problems in the trailer lighting. If not, it in the truck lighting. Sorry, it's a real pain to isolate specific points until it does it constantly. Then you can start pulling wiring and unplugging lights 1 at a time to narrow down the culprit. Other than that, start checking highly vulnerable rubbing spots like the trailer tail lights or hood light wiring.