Esky_addict Posted December 7, 2016 Share Posted December 7, 2016 Hi fellas Ive just finished building myself a new trailer and the lights are playing up they are tardme units with 150mm ish of wire each so needed soldered onto some 5core. I tested them off a car battery before wiring them up and everything worked... but after wiring them up the park/taillights are no go however the number plate light works which is running off the same wire. Even after snipping the number plate light the taillights still wont, go have stripped back near the join in the back off trailer and they will light up with a car battery connected directly to brown wire.Any thoughts? Quote Link to comment Share on other sites More sharing options...
Beaver Posted December 7, 2016 Share Posted December 7, 2016 Dodgy soldering/wiring you added on? Sounds like the lights themselves are working fine? 1 Quote Link to comment Share on other sites More sharing options...
datlow Posted December 7, 2016 Share Posted December 7, 2016 I had this ages ago, turned out to be the cars connector, it worked fine with normal lights as they will still operate down till there's no voltage left give or take, where as LEDs are voltage sensitive so won't work on less then x Volts maybe check with volt meter? Quote Link to comment Share on other sites More sharing options...
Esky_addict Posted December 7, 2016 Author Share Posted December 7, 2016 Wirings done pretty tidy really lol. Getting 11.5 volts at rear of trailer on tailights wire battery is pretty flat too it's on charger at moment but still enough power to run brake lights. Quote Link to comment Share on other sites More sharing options...
Esky_addict Posted December 7, 2016 Author Share Posted December 7, 2016 Getting 13.8 at the taillights with engine running and just swapped wires around so brown taillight wire at car goes to red brake light wire on trailer and they work so that rules out car wiring, Quote Link to comment Share on other sites More sharing options...
chris r Posted December 7, 2016 Share Posted December 7, 2016 Is everything new and or in good condition? Have you tested the car side with a test light? Yes you may have voltage with a test light but if there is a shit connection it may drop off with load. If the car side is good double check all trailer wiring. Quote Link to comment Share on other sites More sharing options...
Mof Posted December 7, 2016 Share Posted December 7, 2016 Check your earth pin in the car plug too Quote Link to comment Share on other sites More sharing options...
Esky_addict Posted December 7, 2016 Author Share Posted December 7, 2016 Everything is new have tested with multimeter aswell. Gotta be a fault with the lights surely? If I run the red brake light wire to the brown tailights wire on the car the brake lights go when headlights are on so this must mean there is nothing wrong with the car side of things. Just seems odd how everything else works fine Quote Link to comment Share on other sites More sharing options...
chris r Posted December 7, 2016 Share Posted December 7, 2016 Double check your join again and maybe test them at the join with a battery. Quote Link to comment Share on other sites More sharing options...
Muncie Posted December 7, 2016 Share Posted December 7, 2016  Make sure your wiring follows this to begin with, both at you car and trailer plug both in then check for resistance across the plug should be minimal like 0.3 Ohm. at least then you will know what end your fault is try using a test light as well some cars electronics wont detect LED bulbs or will just do weird shit. Quote Link to comment Share on other sites More sharing options...
RUNAMUCK Posted December 7, 2016 Share Posted December 7, 2016 Check the polarity. led are polarity specific. 1 Quote Link to comment Share on other sites More sharing options...
Frosty Posted December 8, 2016 Share Posted December 8, 2016 So they work on the bench and when the Brake light wire in the car is used to make the tail lights work? This pretty much means the tail light source wire in the car is the issue, there has to be something causing a voltage drop and that means the connection where the trailer wiring joins into the cars loom or some damage to that circuit in the car. Â This argument only works if the fault lies only with the tail light circuit on the trailer. Â If nothing works on the trailer, brake, turn or tail the argument then swings toward the earth being the issue. ether at the plug or where it connects into the cars loom. I never hook into the cars wiring for the earth and always drill a new hole with a self tapping screw to secure it. I also add a wire that screws into the trailer frame and use that as a common point that every earth on the trailer goes to. You would be surprised how often this simple thing fixes this sort of problem. Â There are some modern cars that need a voltage stabilizer fitted for LED trailer lights but it's rare, my brothers Hilux needed one for his jet sprint trailer. Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted December 8, 2016 Share Posted December 8, 2016 I had to fix a very new ranger recently- the trailer was brand new and worked on one vehicle but did dumb things on the ranger. I ran a multimeter over the rangers plug and it seemed fairly okay for continuity to earth etc but still failed with trailer. Followed wires, popped out a tail light and found that one of those SHIT plastix clip-over wire splicing connectors had popped open. A simple cable tie fixed it but jeez it was hard to diagnose from looking at the trailer lamp operation. Quote Link to comment Share on other sites More sharing options...
igor Posted December 8, 2016 Share Posted December 8, 2016 Does the trailer work correctly on a different car? 1 Quote Link to comment Share on other sites More sharing options...
Esky_addict Posted December 8, 2016 Author Share Posted December 8, 2016 Just had a small breakthrough for you electrical gurus. I just disconnected the brake lights from the trailer plug and the park lights go as normal. Quote Link to comment Share on other sites More sharing options...
Esky_addict Posted December 8, 2016 Author Share Posted December 8, 2016 Frosty I tested the cars parklight circuit by connecting the trailers brake lights to the cars taillight circuit. I was testing wiring on my ba xr6, surf and a mates au xr6 all acted the same. Quote Link to comment Share on other sites More sharing options...
Frosty Posted December 10, 2016 Share Posted December 10, 2016 Those cheap Tard-me LED lights are crap. From your comments I would say the earth in the lights them selves is your issue. A dry solder joint in one could explain the issues. Â There are times when old techniques are better than new ones and I think this is one of them. Beg, borrow, steal or make a test light and check as close to the lights as you can without being silly. If you get a nice bright response for each circuit you can rule the wiring out. If you get a dim response on the tail circuit it would suggest a connection issue with that circuit. If all the circuits are dim then the earth is your most likely suspect. Â It not only takes volts to get a strong glow for a normal bulb but good amps as well, a cheap meter is no help there. 1 Quote Link to comment Share on other sites More sharing options...
Muncie Posted December 10, 2016 Share Posted December 10, 2016 Rule out your wiring. Where are you? I have free time and fridge that needs beer. Quote Link to comment Share on other sites More sharing options...
Esky_addict Posted December 11, 2016 Author Share Posted December 11, 2016 Im in southland man. So just to sum it up everything works fine on these lights except the taillights won't go, the number plate light goes though which is powered by the tailights circuit. However if I disconnect the brake lights from the trailer plug then the tailights will work along with the number plate light as the should, Will email seller tonight and ask but I can't see them coming to the party will probly just get "check your wiring" etc I'm not sure how these leds work as the tail lights and brake lights use the same leds but vary in brightness is there some sort of ballast wire? Quote Link to comment Share on other sites More sharing options...
Esky_addict Posted December 11, 2016 Author Share Posted December 11, 2016 Im in southland man. So just to sum it up everything works fine on these lights except the taillights won't go, the number plate light goes though which is powered by the tailights circuit. However if I disconnect the brake lights from the trailer plug then the tailights will work along with the number plate light as the should, Will email seller tonight and ask but I can't see them coming to the party will probly just get "check your wiring" etc I'm not sure how these leds work as the tail lights and brake lights use the same leds but vary in brightness is there some sort of ballast wire? Quote Link to comment Share on other sites More sharing options...
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