trailer light issues.

[The Quadfather]

I am trying to troubleshoot my trailer lights. About 6 months ago I installed new fully sealed LED lights on the trailer. These are good lights.... But this week I noticed that one of the lights will stay in the full on "Brake" light mode when ever the harness is plugged into the vehicle. EVen if the keys are out, vehicle is off. Therefor I spend all my time keeping it unplugged so as not to run down my car battery. It also means that it is on full tilt brake light, so that particular light does not give a turn signal when requested.
(It would seem that the circut is closed full time?)

How does this one happen?

[curado]

water can cause it

[gian]

if its staying on after the car is turned off sounds like you may have a wire crossed somewhere. Possibly mis labeled harness. It could be a multitude of things. Do your blinkers on the tow vehicle do the same thing?

[The Quadfather]

if its staying on after the car is turned off sounds like you may have a wire crossed somewhere. Possibly mis labeled harness. It could be a multitude of things. Do your blinkers on the tow vehicle do the same thing?

No the tow vehicle blinkers are fine. And it is not a water issue, I'm sure of that. I believe it is a wire crossed somewhere also. It is just frustrating how something can work every day, and then suddenly you have a wire cross issue?? I don't see what there is to cross.... No one is taking apart the harness and disassembling it. Nor the wires at the light.

[racfish]

I' ve owned boats and trailers almost all my life. I have never once had a trailer that the lights ever worked correctly more the 2 dippings in water. I'm always amazed on how lil progress has been made in trailer lights.You'd think in the year 2009 this problem would have been solved. I feel for you Quad. When I tow my boat I just pray that no WSP is behind me watching the lights.Hehehe.One thing I do is unplug lights before launching and retrieving .But even then I got barely working lights.

[Anglinarcher]

I feel your pain, we all do. First, your idea of going to LED lights was a good one, and assuming they are indeed high quality then they are not the issue. LED lights are set in epoxy so water cannot enter and damage the system, but what about the connecting wiring harness?

It sounds to me like a mislabeled wire IN THE BOAT TRAILER is NOT the issue. As you suggested, they cannot work right one day and not the next unless someone is messing with them.

It sounds like you have a short in the system. When you wired it up, you had several locations where you made connections unless you have a custom harness from stem to stern. One of these connections may be shorting or bleeding off to your break lights. It could be due to a wire that rubbed off the insulation, two wires may have moved and are touching bare spots with each other, etc.

I also suspect you have given us the short version and that something else is going on here. First, check out the connection at your towing vehicle with a multi-meter. It takes too much time to tell you what to look for, but note that only drive lights are on "all the time", so if indeed you are getting a light staying on all the time, is is quite possible that your hook-up was not correct in the first place. Boat trailers do not connect to drive lights but to head lights, break lights, and turn lights. On second thought, no light is on when the key is off, so you have a short in the vehicle harness that is dead shorting directly into the trailer harness, or an incorrect hook-up in the first place.

Verify that the towing vehicle is sending the signal correctly to the plug.

Now, assuming all is OK, confirm with the OHM Meter part of the Multi-meter that you do not have a short in your wires. You do this by looking for the resistance of the bulb when connecting from the ground to the plug terminal for each system. You should have the resistance of the bulb, not a zero ohm condition.



Short version, you have bigger problems then you think. I strongly suggest that you seek professional assistance. Again, there should be no signal in your plug from the towing vehicle when the plug is connected if the keys are off and removed. The problem is NOT in your boat trailer, but is in your TOWING VEHICLE. This I really do believe.

[Rollin with Rolland]

It is just frustrating how something can work every day, and then suddenly you have a wire cross issue?? I don't see what there is to cross.... No one is taking apart the harness and disassembling it. Nor the wires at the light.

The never ending saga of trailer lights. I went to a "light bar" a few months back. Basically a complete set of lights that sit on top of my boat, just in front of the motor. I take the light bar and wiring completely off before the trailer even comes within 50ft of water. Basically, my lights and wires have NEVER touched water. Well, a couple weeks back my passenger side brake/blinker went out. Go figure. Hook your boat trailer up to a friends/neighbors tow vehicle, that way you can tell if it's the boat or vehicle...

[Bodofish]

Ground, ground, ground, ground, ground, ground.............. Are we all on the same page?
Wires do not get crossed by themselves. Period! Most all trailers are wired the same, using common bulbs and have a tendency to bleed voltage back through common circuits. Remember, DC current is just like water and follows the path of least resistance. If you have a bad ground on one circuit the voltage will leak into another one causing the wrong bulbs to light. This can be a huge PIA and tough to find.

Take it to U-Haul and make the guy feel like a hero for fifty bucks and save yourself a huge headache.
They deal with with the same crap every day when people rent trailers. Save yourself the headache and get back out on the water. They'll probably fix it while you wait. Last time I had a problem with the trailer lights it did turn out to be on the car and the fixed it for twenty eight bucks and change.

[G-Man]

I'll agree with Bodo on checking the grounding first. I've worked in an electronics related field for 25+ years and there are two things that cause the majority of failures in wiring circuits. Poor grounding and corrosion. One thing that you should never do is use the ball/hitch connection as a ground connection between the vehicle and the trailer. Make sure a ground wire runs into both connectors and are properly terminated in the tow vehicle and on the trailer. Clean all the ground contacts, you need clean metal against clean metal for a reliable connection. Then check and clean all the other connections as well, especially the incandescent bulb sockets. I also dislike crimp connections and solder everything I can, however, if you don't know how to make a good solder joint stick with the crimps. As for bringing it to someone to fix, to me that's a crap shoot. Unless you find a person who gives a darn about their work you'll most likely end up with the same issues a little further down the road. There aren't too many things I hate more than fixing someone elses' kludge. If anyone does know a person who does good, reliable work, post their contact info! Don't just give us a shop name either, of the three folks working a shop only one may know what they are doing.

[Bodofish]

I've used U-Haul dealers from Alaska to Mexico and half way to the other side to deal with trailer light issues. They've always fixed the problems quickly and professionally and on more than one stop they've found dodgy places and fixed those too. I've never been charged more than fifty total for any of the stops. Like I said they, they do the trailer lights thing more than anybody. What do they do? Rent trailers. How many peoples cars/trucks are ready to tow unless you do it all the time????? Not many is my guess. As for specifics the folks on 85th, Rose Hill do a fine job and have fixed a half dozen trailers for me. The owner is always there.

[gian]

When I was thinking of wire cross, the harness points was what came to mind. I have seen harnesses forced and the pins inside bent causing a wire cross. I have also seen corosion from salt water bridge points in a harness. Then there is always a poor/ cheap harness with frayed wiring inside the plastic sheating that arcs on another wire. There should be a ground wire in the harness that is looped to the negative terminal on the battery. If the ground wire just screws on to the undercarige then you might consider heeding the grounding advice given by bodo and gman. Grounding to the car frame always causes problems down the line. I like to run grounds straight off the battery. I'm assuming this is a 4 pin harness - ground, running lights, turn signal, brake? The fact that the lights come on at all would lead me to believe there is some sort of ground present in the loop already, and you have a wire crossed or touching somewhere in the line.

[Bscman]

I went through pretty much the same problem this spring when I picked up my used (new to me) 12ft fishin' setup.
The lights were dodgy at best...

I decided the heck with it and replaced the entire wiring harness on the trailer.
I bought all parts from boaters world (when they were going out of business) but also found the SAME parts/brand names at Walmart. You can get a complete wiring harness with plugs for under $15.

If you don't have a soldering iron, get one! Solder is your friend...crimp connectors are not...crimp connectors are more susceptible to corrosion, and don't take well to vibration or getting tugged on. A cheap soldering iron kit from lowes/sears/etc is $15 or less. Lots of good tips can be found online!

While you're at it, pick up a couple sizes of heat-shrink tubing. Buy the good stuff, and use it to cover any connections (sometimes two layers, even!). Use larger sizes to bulk together multiple wires.

Some zip ties and plastic corrugated wiring looming is also a good idea--100 zip ties is under $5, and a few 4ft sections of 3/8" loom is going to be $6-8. Use the loom where the wires may rub, turn sharply, or on the extensions from the trailer/tow rig to keep the wirings from pinching or wearing through the coating.

So for $50 or so, you'll have ALL NEW wiring that you KNOW is good...not some hacked up, patched mess of wires the pizza faced u-haul kid rolled into a ball and wrapped in tape.

The goal is to wrap and secure all connections (again, no crimp connectors!) so they can't come loose or short out. You also want to protect all wiring that might rub on moving parts, is routed along sharp turns or edges, or has the potential to hang down and snag.

I'm still running incandescent bulbs on my trailer, and have dunked it twice on at least 25 trips this year...and the bulbs are still brighter than they were when I bought it, and still work 100% correctly.