Running lights not working on my four flat trailer lights

[pokman]

Re: Running lights not working on my four flat trailer lights

I had the same exact problem I fixed yesterday. It was my flat four hookup on my truck. If you have a electric tester turn your running lights on and ground your tester and move the positive around in the running light hole. Mine worked at certain spots so I figured it was the connection. 2.50 fix, btw my truck flat four was really corroded.

 

[chargerboy]

Re: Running lights not working on my four flat trailer lights

anybody figure this one out? I just bought a new cargo trailer, and have the same problem. If I hardwire the trailers brown wire to a 12 volt source, all the lights come on. My truck's brown wire puts out 12 volts. The trailer has all LED lighting, is it possible that the vehicle can just not provide enough electricity to power all the running lights? Brake/turn lights work fine for me.

 

[Gary H NC]

Re: Running lights not working on my four flat trailer lights

anybody figure this one out? I just bought a new cargo trailer, and have the same problem. If I hardwire the trailers brown wire to a 12 volt source, all the lights come on. My truck's brown wire puts out 12 volts. The trailer has all LED lighting, is it possible that the vehicle can just not provide enough electricity to power all the running lights? Brake/turn lights work fine for me.

The LED lights pull way less power so that is not the problem.
I would get a new connector for the trailer end and be sure to wire the brown marker light feed to it.There are probably 2 brown wires coming from the trailer.One for markers and one for tail lights.Connect both of them to the single brown wire on the connector.

 

[chargerboy]

Re: Running lights not working on my four flat trailer lights

thanks for the quick reply, i think my connector is fine, as my test was done by jamming stripped wires in it. You are right, there are two brown wires leading into one pin connector, but when I run a wire from a battery to that pin, the lights come on. When plugged in to the car, they don't come on. I know my car has the harness installed correctly as it works well for my other trailers. My friend tried his truck with my trailer, and it doesn't work either.

 

[Outsider]

Re: Running lights not working on my four flat trailer lights

When plugged in to the car, they don't come on.

OK, the car works with other trailers. The trailer works when hot wired, but not with other vehicles known to be hot. Only thing left is to hot wire your car connector pin to the appropriate trailer pin. Jiggle the bejesus out of the trailer connector and exposed wire and you'll find a wire break at the connector or close down stream. Replace that beauty and I bet you'll be fine.

Can someone tell me of any 4-wire boat trailer/commercial wiring harness that has a separate circuit for marker lights. I don't believe I've ever seen that on a boat trailer ...

 

[Bondo]

Re: Running lights not working on my four flat trailer lights

thanks for the quick reply, i think my connector is fine, as my test was done by jamming stripped wires in it. You are right, there are two brown wires leading into one pin connector, but when I run a wire from a battery to that pin, the lights come on. When plugged in to the car, they don't come on. I know my car has the harness installed correctly as it works well for my other trailers. My friend tried his truck with my trailer, and it doesn't work either.

Ayuh,... It takes 2 legs to power an electric light....
You have tested for Power to the lights,...
I'd say you have a Poor Ground....

Hook up a set of jumper cables from the tow unit's Frame to the trailer's frame,...
They'll probably work then, IF the lights are properly Grounded to the frame...
Leds are Very Ground Sensitive...

 

[ghamby]

Re: Running lights not working on my four flat trailer lights

As opposed to Scotch-lock connectors, try something along this line.
http://cableorganizer.com/hydralink-multiple-wire-connectors/
Scotch-locks are unreliable for anything that's exposed and/or prone to vibration. I don't even like them for fixed installations.

 

[chargerboy]

Re: Running lights not working on my four flat trailer lights

re-wired the truck with heavier gauge wire from firewall to brake lights, and heavier gauge wire on the truck side of the trailer harness. Everything on the trailer works fine now. I guess it wasn't getting enough power through the stock wires. I didn't have to tamper with the trailer wiring at all. Hope this helps OP.