Left tail light keeps failing

[Xspook]

The saga continues.

I purchased 2 new LED's and neither one of them work.

The incandescents work fine (less the original problem). When I swap them out using the exact same connectors, the LED's will not work on either side.

I would doubt that I have two bad LED lights. These do not have the "try me" button that some LED lights have on their package, so not sure how to test if they actually work or not...

[K447]

If it was my trailer I would be using a multi-meter to check the trailer wiring continuity, especially end to end resistances, and looking for accidental/partial/intermittent shorts to ground, frayed wires, etc.

It sounds like something weird is going on.

You can test the new LED lamps with a couple of alligator test wires and any 12 volt source *


* This is an easy way to 'make' a 12 volt battery that is fairly 'safe' to use, no chance of a huge spark. Using a PWC or car battery for testing risks a big spark if something gets accidentally shorted.

The 9 volt battery with two added 1.5 volt AA batteries method inherently limits the maximum current.

Plenty of current to light up an LED tail light, not nearly enough current to crank an engine





Tip: The tape wrap just keeps the battery stack from falling apart. The rubber band creates some pressure onto the 9V battery top contacts to make a more stable electrical connection.

[K447]

To be clear, the + on each battery connects to - on the next.

9V + pits touches AA - end

9V - Post touches AA + end

This puts all the batteries in 'series' so that the voltages stack up.
1.5 + 9 + 1.5 = 12 (ish) volts

[pops]

The saga continues.

I purchased 2 new LED's and neither one of them work.

The incandescents work fine (less the original problem). When I swap them out using the exact same connectors, the LED's will not work on either side.

I would doubt that I have two bad LED lights. These do not have the "try me" button that some LED lights have on their package, so not sure how to test if they actually work or not...

Possible the plug pigtail that connects to the lamp fixture has reverse polarity / wired to the harness wrong??

Explains everything here

https://www.etrailer.com/question-93401.html

[Xspook]

Here are the two lamps. Incandescent on the left, LED on the right. Seem to have the same markings as to what connectors go where...

[K447]

... not sure how to test if they actually work or not...

I am suspecting there is an error in the trailer wiring. Perhaps where the replacement connector was wired into the wiring at the back, or perhaps up front at the tongue. Or even, possibly, in the vehicle wiring.

I suggest doing basic wiring checks on the trailer. Do not assume anything is wired correctly, let's verify the wiring is actually correct.

Get a digital multimeter.

And some alligator test wires.



Also buy a spare pigtail connector for the trailer lamp (3-pin connector with short wire leads), so we can test the LED lamps.

Rig up the 12 volt 'battery' thing I posted previously.

Report back, and we can walk you through the testing process.

[Xspook]

I think I have it figured out.

Appears that the ground wire to the side marker light was bad. It splits off of the tail light ground wire. Once I got the new LED working, it flickered when I started to move the side marker light in to place. I replaced that wire and all seems good now...time will tell.

Regarding the LED's not working at all when I swapped them out, they did require a bit of "experimenting" with the connections, but eventually got them going

Thanks to all with the help.

Oh, and to add to the frustration, I ended up blowing the trailer light fuse on my Nissan Frontier and that sucker is quite the PITA to replace! Had to disconnect 6 wiring harnesses just to gain access to the fuse. Then I had to use some elongated curved hemostats just to extract/replace it. I keep a pair of the curved hemostats in my ski to remove garbage from the pump.

[Ratherbeinbimini]

I went through this myself and finally found a nick on the wire running through the tubing of the trailer

[MikeAdams]

Yep....keeping the lights working on boat trailers is a challenge. I agree making good solder connections is the way to go. A while back I picked up a Light Tester box from light-tester.com to check my lights regularly, it is sure a time saver.

Mike

[turboman412]

I always run a separate ground wire to each light from the tow vehicle instead of grounding to frame. I find much more reliable and a much cleaner install.

[AZYAMVX]

Hi. I have a 2008 Triton with a similar problem. My lights used to work just fine, now, brake light or turn light does not work, but when the accessory light on my van turns on, the light works, but turns or brake light does not work. On the picture where you wired your new light, could you specify which wires went to which. Which color did white wire connected to, red and black. I can't quite make out on your picture. Thanks in advance.

[steve45]

Yep....keeping the lights working on boat trailers is a challenge. I agree making good solder connections is the way to go. A while back I picked up a Light Tester box from light-tester.com to check my lights regularly, it is sure a time saver.

Mike

As the owner of 13 trailers, I got disgusted with trailer wiring. Over the years, I found that solder joints sealed with grease and covered with heat shrink tubing really don't hold up well. They're also a PITA when you have to fix one away from home.

By far the simplest, most reliable method of wiring trailers that I've found is to use simple wire nuts. Put a dab of grease in the wire nut, twist the wires together, screw on the wire nut. That's it! If you have a light fail when you're out on the road, just go to Walmart and buy another. You can change it in a few minutes without soldering, crimping, heat shrink, or any of that nonsense.

[johnhoo08]

Good points. I've always heard the left one held a little lower than the right one.....