Utility trailer wiring problem

[winchman]

O.K. Guys,

I have 6' by 10' utility trailer that I pull behind my truck. Lights on the trailer worked fine for about 6 months, but now when I push on the brake pedal the running lights go out. Is there a grounding problem somewhere? If so where? Just thought I'd ask before I tackle the problem. I'm sure someone could steer me in the right direction.

Thanks,
winchman

 

[RobS]

The light bulbs are dual filament for both stop lights and running lights. Sometimes one filament will break and lay across the other one causing the problem you described. You might check the bulbs /w3tcompact/icons/smile.gif

 

[s1120]

Yes, this sounds like a ground problem. Make sure you have a hard ground to the truck! A hitch ball is not a good ground. BTDT [been there, done that]

 

[winchman]

s1120,

How do I get a "hard ground" to the truck using the current wiring?

Thanks,
winchman

 

[s1120]

One line to the trailer is a ground. The white one. Make sure the trailer ground goes into that connector, and that the truck end is hooked up. Some times the ground wire is just hooked to the toung area of the trailer.

 

[Gary_in_Indiana]

I agree on the grounding problem. I swear 90% of the light and wiring problems I've had with trailers (and there have been many) end up being ground problems (or, more accurately, lack of ground problems).

 

[Mosey]

Make sure the ground wire on the harness is getting a good connection at all three points: where it connects to the trailer frame, at the connector, and where it connects to the truck frame. You can’t rely on the hitch ball to provide a good ground connection between the truck and the trailer.

Also, try using some contact grease on the connector and the bulbs. You can get it at an auto parts store.

 

[unaka]

I had the same problem one time with a Hobie-Cat trailer. My father-in-law, who worked for IBM for 30 years diagnosing computer problems happened by. He's a big man, probably 250 pounds.

He perched himself on the trailer, reached down and grabbed the rails with both hands, and then he jumped up and down and shook the whole trailer as violently as he could. The lights came on and have worked since.

I'm not saying this will work for you, but he explained that where the pieces of the trailer fit together, sometimes rust or corrosiion can get in there and mess up your ground.

Good luck

 

[Charlie_Iliff]

Winchman:
Yes, you have a grounding problem. Most trailers use the frame for a ground. (Mine now have a ground wire to each light, as well.) On the truck side, the ground wire will run from the frame of the truck to the trailer plug. On mine, at least, the first place to look for a problem is where the ground wire attaches to the truck frame. Take that off, clean, reassemble and test. Second most common trouble site is where the ground wire on the trailer side attaches to the trailer. (I know that because I completely rewired a trailer before I found that the problem was that the ground wires to the trailer plug were bad on all three tow vehicles I tested it with.)
An initial test to demonstrate that the ground is a problem is to run a test wire all the way from the negative pole of the truck battery to the trailer frame. It needs good solid contact at both ends, of course. When that cures the problem, you have proven what you already knew -- the problem is the ground circuit between truck and trailer.

 

[winchman]

Guys,

Thanks for all the replies! Forgot to tell you one thing in my original post, I have an electric brake control in my truck and frequently barrow a relatives trailer to haul my bota and the lights and brakes on the other trailer work fine. So, the problem must be with my trailer. I use an adapter to go from the 4-flat to the 7-pin on the truck.
Sorry that I did'nt elaborate more on this in the original post!

Thanks,
winchman