I have a 2015 F-150 that I use to pull a 2009 Brenderup Baron. I have had the truck for 3 1/2 years but just started hauling the trailer again last year after. I hauled the trailer I think, 3 times last year and I just plugged it in and went. All lights worked fine. The Brenderup does not have electric brakes so the only wire for brakes is for the brake lights.
After the winter lull, backed up to the trailer and have NO trailer lights. I tested the truck plug with an anemic little tester I had thrown in the trailer and got nothing from the truck plug. Stopped today and invested in a better tester and I had juice to all prongs.
What could be causing the issue? I checked the trailer plug and all contacts were good and I tightened them all. I stick the trailer plug under the frame so it should be protected. Again, all the contacts looked good. Replace the plug? Again, I have NO lights on the trailer. I would think something should work and have a hard time believing all the wiring went poof.
I am trying to do some pre-service diagnosis. Being a woman I get all kinds of BS from most service guys so I am trying to pare down the possibilities.