Boat Wiring Problem. Lights go out w/brake on.

[Traveler1]

Hello, we rewired our boat trailer and now are wiring the plug, it's a 7 pin. The problem is that when the lights are on it's fine except when you put the brake on. When you step on the brake the lights go out on the trailer, and when you use the blinker, both blink. What did we do wrong?



Thanks for any help

 

[SRehberg]

Check to make sure you have a good ground; sounds like the circuit is feeding through the bulb filaments to find ground. This is assuming the wiring is connected correctly.

 

[Joe G.]

Check the ground connection.

 

[Traveler1]

Thank you for the help, we checked the ground and it seems to be solid, but what do you mean, check the filaments? The lights are new and we wired it the same way our other trailer is wired and that one works fine.



I'd check the bulb filaments if you can tell me waht to check, if you don't mind.



Thanks again

 

[SRehberg]

All I was referring to was the path the electricity has to draw a ground connection through. i. e. the only way is through the bulb filaments if there is no effective ground. The path through the filaments is a high resistance ground.



If everything else is correct, I still think you will find a faulty ground connection. The connections maybe solid, but is the surface under the connectors clean or the other ground points clean? Run a jumber from the vehicle ground to the bulb housing, and I bet you'll find that particular lamp burns just fine, possibly all of them if they share the same ground point. Do the lights bolt to the frame of the trailer and do they provide the ground? If so, the metal surface under the housing needs to be shiney bright, or the paint/rust if it exists, makes an excellent insulator.



Are you fighting two problems? i. e. the turn signal flashes both, so are you on the tail light circuit by any chance? I believe the other when you hit the brake is related to the ground issue. The tail filaments will be noticeably dimmer than the brake filaments that are used with the turn signal. I'm sure you knew this already, but had to throw it out anyway.



Good luck; chasing electrical gremlins in vehicles can be maddening, but a systematic trouble shooting plan will weed it out.

 

[Traveler1]

Thanks again, I talked to my husband and he knew what you were referring to and did check, using an LED tester. First thing tomorrow we'll check the connection where the lights are bolted, they do bolt to the frame.



Thank you

 

[Chipstien]

Like has been said... . check the ground. Easy way to check is get a leght of wire and connect it to the frame of both the truck and the trailer. Bet everything would work then.

 

[Traveler1]

Yep, did that too and still the same problem. We'll try the lights where they bolt onto the trailer tomorrow, and hope this is the problem.



Thank you, I think we all agree it's a ground somewhere, and so far they are checking out fine. I'll let you know what we find out.

 

[SRehberg]

If you detach the wiring from the tail/brake lights, then connect the tester to the individual wires one at a time, with the tester ground also connected, does it function properly? This would rule out any mis-wired connections, and you could focus on the ground issue. It could originate at the plug, or even the ground on the TRUCK side of the connector. If other trailers plug into this plug on the truck and work o. k. then that's not the problem.

At least you will have it isolated to the trailer and trailer plug.



I know you'll come across it and then wonder why you didn't hit it sooner. Good Luck.

 

[nfox]

Ground

I have wired up a few trailers and some boat trailers tip when you pull a pin about two foot back from the tongue, and that got me a couple of times, the ground wouldn't make contact where the trailer tilted, so i ran another ground back behind the pin that keeps the trailer from tilting and that solved my problem. Oo.

 

[Traveler1]

Well we never would have thought of this on our own, so thank you all for your help, it was the tilt part of the trailer. Thanks nfox for mentioning that, everything works fine now.



Thank you all again.

 

[Jack in Alaska]

Trailer wiring

Trailer wiring problems... ... ... . it is 95% of the time a bad ground.

IMHO

 

[nfox]

Trailer Wiring

Always glad to help someone out, i have seen some nasty trailer wiring jobs at my previous place of work, you wouldn't believe how people try to cobble up trailer wiring. Oo.