Riddle me this

[Think]

So as some of you know I'm out in Maryland right now and I'm leaving tomorrow to drive back to CO. I trailered my bike home with a homemade trailer from Harbor Freight. When me and some friends finished building the trailer, the left tail light didn't work, but the right one worked fine. We quadruple checked the wiring and everything we could think of and couldn't figure out what was wrong. I figured screw it and I'll fix it when I get home.

I got one of those things that checks to see if there's current running in the wires to try to figure out if it was the tail light, the wiring, or my car that was the culprit. The bulb lit up when I put it against the wiring so there was current running through it so I went out and got a new left tail light.

Now, I install my new tail light in and plug my trailer into my car and neither tail light is coming on and I have no idea why. I disconnected the left tail light to see if the right one might come on again, then I checked the current again and there is no current running through any of the wires on my trailer.

Any help would be greatly appreciated as I'm about to go ballistic.

[SloBlue]

I've fiddled with a lot of trailer lights. I don't know just what's wrong with yours, but usually, unless there is a broken,pinched or disconnected wire, the problem is with the ground. It's hard to get a good ground on the small, light trailers unless you actually run the ground wire through the plug, back to the frame of the car. Hope this helps.

[Think]

I've fiddled with a lot of trailer lights. I don't know just what's wrong with yours, but usually, unless there is a broken,pinched or disconnected wire, the problem is with the ground. It's hard to get a good ground on the small, light trailers unless you actually run the ground wire through the plug, back to the frame of the car. Hope this helps.
Now I feel relatively stupid, or I might in the near future. The ground wire is grounded by a screw on the trailer. To help keep it in place when I got home today, I put some soder on it... would that affect it?

[Sparker]

check to make sure there is no paint under the ground wire connection. i had that problem once. had to grind off all the paint/rust that was around the ground to get a good connection.

[SloBlue]

no, solder shouldn't hurt anything. Check that the ground screw is making a good connection with the metal of the trailer and not just the paint. The problem often is that a small trailer, isolated from the ground by the rubber tires, doesn't have enough weight to make a good connection through the hitch to use the car as a ground. Also, when just testing the lights, guys will not hook the trailer to the car, opting instead to just plug in the trailer to the car, leaving no ground connection at all. Also sometimes the light fixtures themselves are not properly grounded to the frame of the trailer. I've got to take off - good luck.

[Think]

What I don't get is that the ONLY thing I touched regarding the ground wire is adding a little bit of solder to the outside and now nothing on the trailer works. I grounded the paint off from under and around the screw and still nothing. The right tail light was working with just it plugged into the car without actually being hitched.

Edit: I just hitched the trailer to the car and still nothing.

[Keepitgreen]

Check your fuses in the car as well.
Also make sure you are getting good ground when the trailer is hooked up (drive it around the block).. This will make sure the ball is getting good contact..

[Think]

A really nice guy from the local forums here in DC came by and fixed the issue, took about 2-3 hours but it's finally done. The currents weren't grounded throughout the trailer so the lights wouldn't work.

[Keepitgreen]

Safe drive..
Just hit that highway and cock her back!
Don't let off the gas until you smell shit or hear glass breakin'!

[rforsythe]

Why do you guys think a trailer grounds through the hitch to the vehicle? Yes it's metal to metal, but you're talking about a loose coupling (the trailer to the ball, to allow it to turn) through a painted support (the tongue itself) into another painted support (the receiver), all held in by a pin that should have just a little bit of free play so that it can be removed later. There is no suitable ground path through that.

Trailer grounds happen through the wiring on the connector. That's it. That usually is screwed to the frame of the trailer so that the frame continues being a grounded part of the path (convenient for wiring, and a safety thing), but it gets from the vehicle to the trailer through good old fashioned wiring.

[Keepitgreen]

This is true, but I have had instances where the lights didn't come on with older trailers until it was pulled a little bit to "scratch" the ball.
Don't know why, but it worked.
Just what I do by habit..

[Think]

Well my trailer is foldable, so right where it folds it was losing the ground through the frame. We finally scratched paint off around some of the bolt holes to keep the ground going.

[OUTLAWD]

could possibly get some tek screws and a small jumper of wire to ground the trailer across the foldable section

Drive safe mang!