I just put all new LED lights and wiring on a small trailer a few weeks ago but never tested them so it's just been sitting in the garage till tonite when my boy wanted to borrow it. We hooked it up to his truck but no lights. I did weld a couple of chain links on the tongue to keep the safety chains up off the ground after I got done with the lights and wiring and don't think welding should of hurt anything but I kinda wonder now. I haven't went through and checked any thing other than the ground but it checks okay and I have power and ground on the vehicle. I'm dead tired and have had enough for one day so I'll do more testing tomorrow but the welding thing keeps bugging me. Any thoughts?
Would Welding on Trailer Smoke LED lights?
- Thread starter i4ni
- Start date
Viper98912
Well-known member
Were the LED lights grounded to the trailer frame somehow? If yes, then maybe you did burn them...
if there wasn't a path for the current to travel thru the feed wires , I don't think it would affect them
manwithtools
ALLIANCE MEMBER
No, there should be no issue regarding welding and LED lights. Zero, none.
I spliced and soldered the plug end of the harness so I could run it inside of the trailer tongue so maybe there's an issue there. I did that part outside and it was getting dark and of course nothing was co-operating so who knows. I remember a lot of cussin going on lol.
Moss
Well-known member
I doubt welding would damage them. Check your polarity. Many led trailer lights use white for negative and black for positive.
FredWanaker
Well-known member
probably not but some forms of welding create a lot of EMF, and led's don't like strong EMF. Pull one off and hook it to a battery to see if it will work off the trailer. You can probably just disconnect one wire on it and try unless the white is not the ground on them.
619DioFan
Well-known member
My trailer doesn't have LED lights but I have welded on it with my lincoln 220 stick welder with zero issues.
Jarwop
Well-known member
run it inside of the trailer tongue " "How close are the wires where you welded? Maybe the heat melted the insulation on the wires...
TractorJeff
Well-known member
How do you know the truck connector is wired properly or working? How did you test your installation wiring the first time? How do you know the plug on the trailer wiring matches the truck receptacle wires?
Jazz1
Well-known member
Many of our highway trailers are cobbled together with miles of welding and no issue with the LEDS,,,each unit would have 2 dozen…
Wrench97
Well-known member
I welded on semi trailers with LED lights all the time never blew one in 20 years.
This is what I would be checking on.
Spiral wrapped and welded links to the top of tongue but you never know
Factory trailer package on new truck. Wired trailer to the industry color standard but who knows I suffer from brain flatulence on occasion.
I tend to be very thorough by nature (in other words most of the time I'm a compulsive over thinker and therefor frustratingly slow) but that doesn't mean I don't make mistakes "obviously lol" so I'll double check my work and test each wire and connection. At this point I'm thinking it's going to be a poor ground or a failed solder joint. I'll update when I find the problem.
Two Speed
Well-known member
Ford has been known to provide a trailer connector, but not hooked up to anything on the truck. Also check that the fuses are installed for the trailer hookup, I forget who does (did?) it, but fuses on the trailer wiring get shipped uninstalled.
This is a new Chevy PU and my wife's 2019 Forester, both have power to the clearance/Tail light pin (brown). I didn't bother checking the turn signal /brake wires at the time but I will. I probably won't get back to working on it till midweek but as I said earlier I suspect a poor ground or a bad solder joint. I've noticed in recent years that sometimes brand new terminals (China) need a little sanding to get a good connection especially if the coating is bright plated looking whereas Your older USA terminals had more of dull galvanized coating and rarely caused problems when new. Like most electrical issues it's bound to be something simple.
I recently was pulled over for left side trailer light not working. I asked if i could get out and look. when i did i seen the bolt that connects from the light to the angle iron was broken "not grounding the light" i had the ranger 8 on the trailer and aske the cop if i could weld it to the angle iron and the light should work again.... he said sure.
short story, led light works again and i didn't fry it, nor did i melt the plastic
short story, led light works again and i didn't fry it, nor did i melt the plastic
laser3kw
Well-known member
shouldn't have hurt anything (unless melted like mentioned)
Is the trailer a tilt trailer? Mine is and I had to run a jumper from the tongue to the frame. The hinge pivot would not conduct a reliable ground when tilted. Test it by using a jumper cable from the truck chassis to the trailer frame.
Is the trailer a tilt trailer? Mine is and I had to run a jumper from the tongue to the frame. The hinge pivot would not conduct a reliable ground when tilted. Test it by using a jumper cable from the truck chassis to the trailer frame.
RPH
Well-known member
Depending on the type of weld ac versus dc you can fry the module. Even with dc I see the potential for noise to create an issue.I would most definitely check the wiring but in the module itself there are different connections on the ground plane internally. One specification I would be concerned is peak inverse voltage on diodes, also the capacitors voltage limitations can be crossed. Either of those along with any solid state devices could burn up. 25 -50 volt working dc is not uncommon spec for caps. The schematic presented is one that shows a generic driver for the led array. I see plenty of potential for damage. You only need a difference in potential to create an arc. Q1 and Q2 are likely candidates.
niget2002
Well-known member
I'm having issues with led lights on a small trailer too. The cheap kit I bought doesn't seem to put enough load on the vehicle or something. I plugged one of those small brake light testers inline with the trailer and they work.
You could be having a similar problem.
I picked up some load resistors to solder in parallel with the brake lights to see if that fixes the problem.
You could be having a similar problem.
I picked up some load resistors to solder in parallel with the brake lights to see if that fixes the problem.
Often, it's the 12v power feed that is left open at the fuse box, not the lights.
Having not tested them makes it impossible to say if the welding did any harm or not. Btw, you should always disconnect the neg batt cable whenever you arc weld on any vehicle.
laser3kw
Well-known member
a load resistor would go in series.
dcg9381
Well-known member
Many trailers have lights that are grounded to the frame.
I've welded on lots of them with LED lights. I have "yet" to have an issue, but that's not to say that a welding arc couldn't induce enough current in a wire to fry something electronic on an LED assembly.
I start all my "trailer light" diagnostics with a tester at the truck itself... I carry a 4-pin tester on my keys.
I've welded on lots of them with LED lights. I have "yet" to have an issue, but that's not to say that a welding arc couldn't induce enough current in a wire to fry something electronic on an LED assembly.
I start all my "trailer light" diagnostics with a tester at the truck itself... I carry a 4-pin tester on my keys.
rockinacummins
Well-known member
I’ve welded on a lot of trailers and have never seen it cause any issue with the lights, LED or otherwise. However, I would not be surprised to see the sensitive electronic components of an LED to be affected.
Got a chance to work on the trailer today and it turned out to be poor grounds at both clearance lights.There is no ground wire on them and instead they ground through a metal eye that the mounting screw goes through.Although I knew better I took a chance using the old screws rather than driving a half hour to pick up new ones.Those 4 screws were the only parts that were not new and I ended up screwing myself not taking the time to drive to town. Oh Well lol. Thanks for the help guys
It wasn't hooked up to a vehicle while welding, I was taught that long ago. Thanks
niget2002
Well-known member
Pretty sure it's parallel.
You want the current to increase, but you want the voltage to the LED to still be 12v. If you put it in series, then the LED won't get the full 12v and will be dimmer.
laser3kw
Well-known member
a little confusing circuit descriptions.
I was confusing the "discrete" LED, like the red or green you see on a device., Those will have a series resistor to limit current through the LED. A parallel resistor I normally consider a "shunt" for whatever reason it is there.
I did a little reading and it seems Automotive "LED" lights have a different format. I assume(!) because of the multiple LED's within a single bulb, they kind of self regulate the current so they don't melt down. That's where the parallel "load resistor" comes in. The circuits are designed for conventional lighting whether it's Halogen or incandescent. The different control modules look at the feedback current from a bulb to determine if it is functioning properly. When LED lights are put in, that monitoring current drops and the control modules think there is a problem. That's where the parallel resistor "shunts" current around the LED bulb to re-establish the correct current flow for the control module to be happy. That's my crude explanation of what I read.
But then I just rewired my small flat trailer last year with all LED kit. It did not exhibit any problems with turn signals or other lights when hooked to a 2018 electric system
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niget2002
Well-known member
Yeah. Agree. When I first had the issue I went and read too. My background had me thinking the same as you until I read that the LED tail light should be viewed as a system and not an individual bulb.a little confusing circuit descriptions.
I was confusing the "discrete" LED, like the red or green you see on a device., Those will have a series resistor to limit current through the LED. A parallel resistor I normally consider a "shunt" for whatever reason it is there.
I did a little reading and it seems Automotive "LED" lights have a different format. I assume(!) because of the multiple LED's within a single bulb, they kind of self regulate the current so they don't melt down. That's where the parallel "load resistor" comes in. The circuits are designed for conventional lighting whether it's Halogen or incandescent. The different control modules look at the feedback current from a bulb to determine if it is functioning function. When LED lights are put in, that monitoring current drops and the control modules think there is a problem. That's where the parallel resistor "shunts" current around the LED bulb to re-establish the correct current flow for the control module to be happy. That's my crude explanation of what I read.
But then I just rewired my small flat trailer last year with all LED kit. It did not exhibit any problems with turn signals or other lights when hooked to a 2018 electric system
Either way... I have two load/shunt resistors sitting my desk waiting for me to find the time to go install them on the little trailer. Probably be sometime over the winter when I rebuild it.