I Recently added some LED side markers to my trailer. I tapped into the brown wire and the side markers light up but once I Wire them all up with the rear light the side marker don’t work anymore but the rears do. If I disconnect the rears then the side marker works. I have cleaned all the grounds and ran a new wire to the rear lights still not luck of them all being on. Any suggestions?
It’s still your ground. LED lights are super-fussy about the ground. They are not like incandescent lights where a poor ground just makes the lights dimmer, most LED lights are either on or off as far as the ground, if the ground isn’t good enough, the lights don’t work at all.
In the past, I’ve solved LED ground problems by adding a dedicated pigtail ground from the tail lights directly to the frame by crimping on a loop connector on a short lead. Then use a Dremel to clean to bare metal somewhere on the frame and drive a self tapping screw. Cover the entire spot then with liquid electrical tape so it doesn’t corrode. If you’re fussy about your trailer, you can always make this unsightly hole on the back side of the frame where it can’t be seen.
Make sure all other grounds are good and where the bolts for the light are the ground, make sure everything is clean and then cover with contact grease.
Do your LED markers have 1 wire or 2?
If 2 wires are they color coded?
Stay away from using the frame as the ground, use a dedicated ground wire and 99% of your trailer lights issues will never happen.
LED stands for Light Emitting Diode, A diode is a 1 way electrical device. Depending on how and where you “tapped” into the wire may also be your issue.
They 2 one white one black. I’ll give the jumper a try and also back through and clean the grounds again
Since we are talking trailer wiring which I hate tremendously…. I am not an expert and it seems like I see enough problems with non-working trailer lights that I need to improve my knowledge a bit.
What is the grounding issue with trailers?
There is a ground wire coming from the wiring harness on a truck and the trailer wires plug in to which I would think should be sufficient. But I also seem to experience the grounding being handled through the trailer being connected to the truck hitch/receiver. Relying on a new truck receiver with fresh paint or a rusty receiver seems like a poor concept for obtaining a ground.
Is the ground wire in the harness not making a good connection when the trailer is relying on the hitch connection?
What is the grounding issue with trailers?
The “quick” and frequently used method of trailer wiring is that the frame of the trailer is used as the ground conductor, so there is a hot wire that runs to each light (the actual wire), but then the ground of the light is just connected to the trailer frame, which leads back up to the tongue where the wiring harness usually just has a short section of wire connected to the frame.
In an ideal world, this works because the trailer frame is a conductor. In the real world, it just gives you lots of places for things to go wrong. You have an iffy connection at each light where it is connected to the trailer frame and an iffy connection at the wiring harness where it connects to the trailer frame. Add to that the fact that these connections frequently get wet and you have a recipe for rust. If you get any corrosion in the connection, you’re not getting a solid ground.
The best solution I have found is to run a ground wire to each light so that you’re not relying on the frame for a gound. Solder and shrink wrap each connection, and you virtually eliminate ground issues. It takes a little more time and money up front, but I hate chasing down trailer light gremlins.
I Recently added some LED side markers to my trailer. I tapped into the brown wire and the side markers light up but once I Wire them all up with the rear light the side marker don’t work anymore but the rears do. If I disconnect the rears then the side marker works. I have cleaned all the grounds and ran a new wire to the rear lights still not luck of them all being on. Any suggestions?
Trailer wiring has given me a lot more gray hair over the years and I (like almost everyone) hate them with a passion. For reasons stated above, I run a dedicated ground wire from the wire harness out to the device string. More than anything, it eliminates the impedance difference on the ground. I had one light dim, another bright, and every issue in between. The dedicated ground took care of the vast majority of issues.
Then the wonderful world of LED’s came into play. I’m not an expert on LEDs and can only share some experiences. Some LEDs play nice with others and some don’t. I know in tail lights, the draw of LEDs is so minimal, the vehicle’s relays and sensors sometimes can not detect them as in the case of directionals blinking. I replaced all my side lights on the slide in camper with LEDs and still had the old incandescent 1157’s and such and had the same problem you have. After many phones calls and tech support, I found out that brand or type of LED wasn’t capatible with being on the same string as the old lights. Why??? never got a direct answer, just had to swap out the old lights for new LEDs and they all work. Had a similar issue on my boat trailer with some working or dim and others bright or didn’t work at all. After dealing with that BS for a week, found out different brands don’t always work with other brands. WHY?? Again, I never got a straight answer. Fortunately with the boat, I got everything through Etrailer and they were great to work with. Sent all compatible stuff out to me and a RA to return everything else. They expedited shipping and I was done in a couple days.
The last two enclosed trailers I did were a little more extensive. We converted to RV plug, added switched floods, interior on constant power, back-up,and all new LEDs throughout. We pre-strung the lights and tested it before installing. An additional step that we probably didn’t need to do, but was well worth knowing we had it right.
forgot to mention, if I have to splice any wire on a trailer, these are almost the ONLY splice I’ll use. Gel filled and prevent corrosion
I addition to Ralph’s post above, I’d just add this.
Basically, either from the factory or when trailer lights have been redone, most of the time the workmanship is shaky at best.
Trailer wire tends to be cheap and undersized, so the resistance is already at a marginally acceptable level. Again, “in an ideal world”, things should work, but with high resistance already being a problem becuase of wire size, there is very little margin for error. And then…
Add in a bunch of half-ass quick connect pinch on splices, a bunch of rusty non-waterproof butt splices that were done without shrink wrap over the top, some half-ass twisted together wires, rust and paint inhibiting every ground connection, etc, etc. and the only surprising thing really is that any trailer lights ever work at all.
Add in a bunch of half-ass quick connect pinch on splices, a bunch of rusty non-waterproof butt splices that were done without shrink wrap over the top, some half-ass twisted together wires, rust and paint inhibiting every ground connection, etc, etc. and the only surprising thing really is that any trailer lights ever work at all.
AMEN
Also, buy a $20 50′ All weather Extension cord, 16/3 and use that for wiring… the cheap plastic coated 3 strand stuff lasts about 5 or 6 seasons in MN.
Hi all, I’m wiring my towbar lights into my car.. on wiring the right indicator light, the trailer indicator works when the cars rear lamp is disconnected,as soon as I plug in the car light the indicator on trailer stops, any ideas ??
Hi all, I’m wiring my towbar lights into my car.. on wiring the right indicator light, the trailer indicator works when the cars rear lamp is disconnected,as soon as I plug in the car light the indicator on trailer stops, any ideas ??
What I would bet is happening here is that when you plug the cars light back in there is not enough current available for the trailer light to function properly.
See my post above. LED trailer lights are very fussy as to both available current and ground. In the old days with incandescent lights you could get by with 11 volts and your lights would just be dim. LED lights absolutely will not function if the voltage or amperage drop below their requirements.
It sounds like you are trying to tap into the wiring harness in the vehicle. In modern cars with their micro-sized wiring that can be difficult to do.
Are you sure your vehicle doesn’t have a pre-wired place to connect a trailer harness?
Hi thanks for the reply. This is exactly what I thought but I don’t know why as the left side works perfectly. Is there anything I can do ?? Also I’m not sure if it has dedicated wiring to be honest not much of an expert on this stuff but wouldn’t have thought so as the corsa has the towing capacity of a mobility scooter
How are you tapping in to the turn signal lights on the car? I hope you’re not using those pinch on connectors that bite into the wire?
Those quick lock connectors are Satan’s plaything. Absolutely do not use them. They are completely useless and in any application with corrosion or vibration – – which is basically every application in Marine use, they will fail.
The best connection as far as not causing resistance is to solder the wires together. Barring that a good crimp connection can be nearly as good.
Also make sure you check the ground on the tail light side. Make sure if it has a dedicated ground wire it is connected to clean bare metal.
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