Okay, the new boat has a 5-wire system due to the surge brakes.
I have no tail lights, but the running lights work.
I took apart the “circle adapter thingie” and all the wires in there are connected. I pulled back the about 3 feet of conduit that goes over the trailer wires and no problems there.
I have no brake lights or tail lights. But, again, the running lights work up front.
Two blown bulbs in back, maybe:question: That’s my only idea…
Ditto on checking the ground. Often a trailer is wired with the trailer frame being the ground. If that is the case, each light has to be bonded ( grounded) to the trailer. Check to be sure the rear lights are bonded to the trailer.
Some lights have a bolt to the light fixture and the bolt actually is the ground. May want to disconnect bolt and clean trailer frame with sandpaper and put a new clean washer on the bolt that holds the fixture to the trailer if the fixture does not have a seperate ground wire. Good Luck.
Just thought of something, Take a wire and strip both ends and hold one end to the ground on the light fixture and the other end to a non corroded area of the trailer ( get a good ground without any doubts to the light not working) and see if the light comes on. If so, your problem is a Bad Ground if not you may have another issue.
A good tool is the ice-pick probe with a ground wire and a light in the handle. Available at the auto parts store. It works better on 12vdc than a meter because of the load the light puts on the system. Turn the lights on the trailer and probe around, you’ll find the problem quickly.
Good luck.
I just rewired my trailer and put guide posts with the LED lights at the top. I went to plug it in and I got nothing but the blinkers to work. After spending a while checking all the wires and grounds I finally thought to check the fuses and it was a blown fuse. So moral of the story is check your fuses. That is a lot easier than tracing all of those wires.