7-pin trailer connection tester WISHES

[Sodo]

I can find ways to get the info.... but a tester that tells me instantly if its the truck or the trailer, and where, is best. Then when I fix it I want to test immediately and not go looking for help. I don't have any windows to use etc. But I do have a bluetooth snake-camera that might work out. Undoubtedly there will be fussing though, updating the app etc, it goes on and on.

The long extension cable so I can park in view of the lights is a great suggestion.