North Australian FISH FINDER TM forums

Trailer lights won't work. Probably only 11 months old .LED's .Hooked up to ute, motor running, but no stop / tail / indicators!!!!!Test with test light, power to both sides of trailer. Is this a coincidence that all lamps have died at once or have I overlooked something simple? I really need some help or comforting. What the fark am I doing wrong or missing?

Check out the earth lead back to the tow vehicle.

No return path means nothing works as all the lights use the one common earth/return wire.

25 year question i have never been able to answer


Boat trailer lights have had them all fully sealed, LED , light boards one or two trip wonders all of them......WTF does my head in...........

ronje wrote:Check out the earth lead back to the tow vehicle.

No return path means nothing works as all the lights use the one common earth/return wire.

Another option- are the lights working on the car it self? If not possibly a fuse in the car.

Probably Ronje's suggestion but if not try this.

If there're LEDs its probably the plug near the lights at the rear of the trailer .
Most likely corroded , I've had this twice and gave up and use a light board

Thanks for the input so far blokes, with test light clipped to trailer at the tail light, I have got power, is there something I am missing re earth back to ute???
That is ,I have got power for taillights and power for indicators so therefore I have earth or don't I ???? I thought that the towbar itself was the earth back to the ute........ WTF.

Had enuff brain teasing for the moment............worry about it next year. So thanks all for so many entertaining and educational posts I'll wish you all complements of the season and hope to be reading and posting this time next year.............. Get stuck into the brainfood (Bundy) have half a dozen and you'll know everything. Cheers

Have sent you 2 PM's with the information you require to test your lights
Regards Shaun

xxxx wrote: with test light clipped to trailer at the tail light, I have got power, is there something I am missing re earth back to ute???
I thought that the towbar itself was the earth back to the ute........ WTF.

Earth should be through the white wire not through the trailer body. Unless the lights themselves are physically earthed to the trailer earthing will not be through the trailer and tow ball (not even sure that would reliably work).

As Jeff said, most likely a break through corrosion somewhere in the cable.

Wiring diagram below.


http://www.narva.com.au/products/browse/wiring-diagrams

Yep That's what I sent him dannett

Yep earth wire knackered and when using the test light you are grounding to the trailer which is connected to the car through the towball.......bet it won't work if you un-hook the trailer and chains .

You'll notice that the earth wire is white on all of the diagrams that dannet posted. That white wire should go to each of the lights as its the return/earth lead for every electrical thing on the trailer.

Its purpose is to give a good reliable return point for the electrics on the trailer.

If the towing electrics have been done properly, you'll have no trouble checking wires. If it hasn't been done properly, none of the colours will make sense and you'll need help to sort it out.

If that white wire is corroded or broken at the trailer plug or the back of the tow vehicle socket then there wont be a reliable ground/earth return path for the trailer electrics to the vehicle electrics.

The only electrical earth will be via the towball and chain which will be a high-resistance point to the vehicle chassis.

High resistance means that you will read voltage at each light to the trailer body BUT:.. no current will flow. Therefore no light/s will work even though voltage appears to be present at each light.

Look for a broken or corroded white wire on the plug on the trailer wire OR from the back of the socket on the car. Follow that white wire to where its connected to the chassis of the vehicle.

Mostly the white wire from the back of the towing vehicle socket simply goes to a return wire from nearby indicators or tail-lights and is crimped for electrical connection purposes. Unless done properly ALL crimps will fail electrically sooner or later by corrosion etc.

Thanks heaps for your input and assistance , you blokes should be fishing instead of wasting your time on a wiretwanger like myself..
Tight lines...smelly fingers...and a great new year to you all