Help Needed With Tail/Marker Lights

[Rob & Mel]

Hi There,

I am having trouble with my trailer tail and marker lights. I hooked them up to the tow vehicle today and at first nothing worked. I tested the tow vehicle to make sure that it was putting out power and everything checked out fine there, so I know the problem is with the trailer.

Since nothing was working at all, I first checked the ground wire on the trailer. It seems fine and there is plenty of a connection being made to bare metal. So I moved to the marker lights next to see if they were the cause. When I installed them I remembered the little metal tab that holds the light in place possibly makes a ground. Since I widened the trailer, these lights are now attached to wood, so if the tab does ground it, it wasn't making a connection. So, I ran a ground from each little tab to the trailer frame.

So now, the marker lights work, but they blink no matter which direction the turn signal is going, so they are more like hazards. Plus, the tail lights don't light up, even when the brakes are engaged, and the tail light blinkers on the side of the tail light are very faint, but light up appropriately when the turn signals are on.

Please help me figure this one out! I am not good with wiring but I thought I hooked everything up right. The lights I used are the standard lights that come with a Harbor Freight trailer, and I wired everything to the corresponding color just like I was supposed to. I need help with this one, so any info is greatly appreciated.

-Rob

[Rob & Mel]

I think the problem may be with the grounding on the back lights. I believe that the ground for these lights is made inside the light enclosure via one of the mounting bolts. Tomorrow I am going to jump the back tail lights to the frame too, and see if that fixes it (the tail lights are mounted on wood too). If that doesn't work I might run the ground wires from all the lights back to the original ground point on the trailer, and possibly to the tow vehicle itself through the white ground wire. I'll let you know if that fixes the problem.

-Rob

[bobhenry]

I might run the ground wires from all the lights back to the original ground point on the trailer, and possibly to the tow vehicle itself through the white ground wire. I'll let you know if that fixes the problem.

-Rob

Now you are cookin' hard wired grounds all the way back to the tow vehicle.

Intermittant and poor ground will make the light do some really wierd things. Nothing worse than to think you are iluminated to be better seen just before someone runs over you because the didn't see you in the dark without the lights you thought you had !

[Rob & Mel]

Woooo!

Trailer lights are now functioning perfectly! The problem was the ground, needed to ground all four lights to the body to make everything run correctly. I still haven't ran them all to the tow vehicle ground, but will do when I get some more wire. For now though, I am registered! And insured! Oh yeah!

Bob Henry,

Thanks for the reply! I gotta also give you credit (and user Nobody) for the tongue extension advice from a different thread. Glad I found that one and heeded your warnings...

-Rob

[bobhenry]

The Harbor Freight trailer tongue extention and re design was all Harvey ( Nobody's) baby.
I simply copied his lead and it is probably the single best thing I have done to improve the trailer. I would also like to thank Harvey

[Nobody]

Comments (& flowers) noted & appreciated guys. The tongue ext is also my best 'mod' for towing & ease of handling. We've pulled the TD more'n 12K miles now with never a hiccup. I also credit the tongue ext with adding to the strength/rigidity of the HF chassis in the rear end collision I experienced Labor Day weekend 2010. If not for the added strength (which by-the-way bent the hitch receiver on my TV) I think there'd have been much more frame damage to the TD. The TD is sitting outside near the patio as I type, ready & waiting for a quick trip somewhere (anywhere ) just as soon as Ma & I get a break from our babysitting duties

[katrinad]

Looks like I have the same problem. Can't get any of my lights to turn on no matter what. I did extend the frame, but the back lights are on the original brackets to the frame.

Side lights are on wood, so I'm running a ground wire now.

How can I fix the rear lights?

[Dale M.]

IF you have a full welded frame you can probable get away with a ground bond from frame to metal shell of trailer or to each light....

If you have bolt together frame you probably need run full ground wires along with the "power" lead to each lamp fixture...

I have always had god luck with trailer frames that were welded... Not so much with bolted together.... Its usually the paint at each joint being an insulator that will not allow a good ground path...

While a full wired ground system to each fixture may not always be needed, it is the only way to ensure you are doing the right thing to prevent grounding issues....

Dale

[CarlLaFong]

What a lot of people don't realize about DC is that electrons flow from negative to positive. What we, commonly refer to as a "ground" or "earth" is incorrect. It is part of the complete circuit that is required for stuff to operate. The ground, or green wire, in an AC installation actually is a ground. I think that is why there is, often, so much confusion about grounds and their function

[katrinad]

Took another day but once we added our own ground wires from every light it ended up working. Don't know why they supply lights with the trailer that won't work without extra crap!

[Dale M.]

Took another day but once we added our own ground wires from every light it ended up working. Don't know why they supply lights with the trailer that won't work without extra crap!

You inadvertently said it CRAP! Chinese Republic Authentic Products...

Dale