Canepole or any electrician, question on bulb polarity

[Cane Pole]

A two conductor arrangement can become complicated. LEDs have complicated the world.

[LBM]

The continuning seemingly never ending hassel with boat trailer wiring was eliminated for me when I had LED lights installed with the trailer rewired with a third white ground wire run to each light so as to not use the trailer frame for return ground. Previously for me 99% of the time all my trailer light issues resulted from faulty ground wire and the screw into the trailer frame. That upgrade was done in 2009 and I haven't had any issues since. Knocking on some wood here hoping I don't have a trailer light issue the next time out.

[Cane Pole]

Frame grounds do not work well over time. We have to learn this lesson over and over with our cars, our boats, and our aircraft and other moving objects such as trailers. Frame grounds were not used in the Apollo Project!

[Slab]

The goofy thing is, there are two wires running to every light. No real need for a ground, but they grounded the darn thing with the screw that holds it to the frame. And they grounded the wrong end of the bulb, therefore requiring backwards wiring, which is fine for an incandescent bulb, but not an LED. Replacing the screw with a nylon one like BB suggested is the perfect solution. Yeah of course simply replacing the fixtures with sealed LED ones is the ultimate way to go, but I'm too cheap. I already replaced the four big brake/running lights with sealed LED lights and they are great. I was simply trying to stick LED light bulbs in the remaining dozen marker lights when I ran into this reverse polarity issue.

[JD1]

Thanks for this thread. Didn't know that LED's were different.

[crappie wrangler]

I replaced the lights on a friends boat trailer recently because all of the fixtures were broken. Just bought a LED trailer light kit and while I was installing it I noticed there was a ground wire at each fixture in addition to the standard lighting wiring. If the extra ground wire was not grounded to the trailer that light would not work. To be a little more specific, the tail lights had the standard 1 yellow and one brown or one red and one brown but each had an additional white ground wire which leads to the question " how is your grounding"?

[Slab]

I replaced the lights on a friends boat trailer recently because all of the fixtures were broken. Just bought a LED trailer light kit and while I was installing it I noticed there was a ground wire at each fixture in addition to the standard lighting wiring. If the extra ground wire was not grounded to the trailer that light would not work. To be a little more specific, the tail lights had the standard 1 yellow and one brown or one red and one brown but each had an additional white ground wire which leads to the question " how is your grounding"?

Not sure why a positive and a negative wire going to your light would not work unless grounded too. But a light bulb should definitely light up if it has a positive and negative wire with juice flowing. And in the case of LED lights, the juice has to flow the right way. All I can think of is, your other negative/ground wire is not connected good somewhere. Or since you mention it's brown, what I see on etrailer.com is that the brown wire is your running lights: https://www.etrailer.com/faq-4-5-way...eshooting.aspx If that's the case, that fixture would certainly require a ground connection (my trailer has separate white wire for negative/ground).

["G"]

A LED ( light emitting diode) A diode is really like a one way check valve....current will only flow in one direction through it.

[Cane Pole]

A LED ( light emitting diode) A diode is really like a one way check valve....current will only flow in one direction through it.

One way, like some streets and some people. I say to some folks, "you diode". The message is most often missed.

[Slab]

Now I understand evetrything!!!!!!