Trailer lights issue.

Eyefor

Well-Known Member
Help / advice required please.

Just had an Ifor Williams trailer upgraded to LED lights all round (10 in total) as some of the old (bulb type) ones were busted or bulb gone.

Now the trailer lights will not work with my car which has the 7 pin socket.

Attached another car and the trailer lights work perfectly. Attached my car to a light board (with bulbs, not LED's) and all work fine but the indicator bleeper is now not working.

Any ideas what is going on please?

Thanks in advance.
 

bobthedug

Well-Known Member
Sorry I cannot help specifically but I bought a trailer recently with a brand new board with led lights fitted. It wouldn't work at all when plugged into my 7 pin socket. Tried the old board the seller had in his garage and it worked fine in my car.
Both old and new boards worked fine in trailer sellers car but the led one didn't work in my car at all.
I gave the new led board away as sorting it out was beyond my technical abilities.
 

Overlay

Well-Known Member
check the pin numbers on the car and plug you may need a conversion spacer plug
i had that on my IW trailer
 

Eyefor

Well-Known Member
You may need a resistor kit adding as the LED resistance is very low…meaning your relay or car doesn’t recognise a trailer is connected?

The other car may be more modern and thus accepts LED lights? Just a thought.
Thanks for the reply. I can see that making the bleeper not work, but why would that make the lights not work at all when they work fine with a light board and another (non LED) IW trailer.
 

Overlay

Well-Known Member
yep
when i got my trailer new - lights wouldn’t work, it needed the multi pin conversion to work, sorted it at source from the shop
 

Eyefor

Well-Known Member
yep
when i got my trailer new - lights wouldn’t work, it needed the multi pin conversion to work, sorted it at source from the shop
That would mean your trailer has 12 pin and your car 7 pin so hence the need for an adaptor? Both my car and trailer are 7 pin.
 

Norfolk Horn

Well-Known Member
My L200 on a 19plate dosnt work with the led lights on a trailer or the mot testers plug in. I know this as I had a problem with the lights not working at all when I got it due to a fault.
It may pay to Google your make and model and see what comes up as my trucks problem was documented.
 

rem284

Well-Known Member
Ford ranger, often if i am plugging into a different trailer the trailer lights will not work for a short period then they do. Sometimes this is an hour, sometimes a day. It's as if something in the pickip takes time to recognize things
 

rob4586

Well-Known Member
Thanks for the reply. I can see that making the bleeper not work, but why would that make the lights not work at all when they work fine with a light board and another (non LED) IW trailer.
I think some smart relay have to recognise the load/resistance as within a valid range before switching the power on? Not saying this the case, but just a thought. LEDs cause problems in lots of electrical applications where retrofitted due to very small resistances.

Cheers, Rob
 

kripton

Well-Known Member
Probably a silly suggestion (but I know nothing about electrics) have you tried reversing the polarity of the bulbs? - I installed LED lights on my boat and some worked and some did not - They all worked however when I reversed the "dud" bulbs
 

Skietindiekop

Well-Known Member
Thanks for the reply. I can see that making the bleeper not work, but why would that make the lights not work at all when they work fine with a light board and another (non LED) IW trailer.
What car is it?
VW group and others uses Can Bus that needs to see a certain load and so some are fine and others need a resistive load to work
 

Jimbob39

Well-Known Member
LEDs have no load, this tricks the car into thinking there’s actually nothing connected. Need a resistor to create a load that simulates bulbs. Most decent LED lots I’ve these as standard. Used to tuck a 20W bulb up under the trailer side rails when we started fitting them on trucks many moons ago. Better options out there now.
 

wytonpjs

Well-Known Member
Having similar issues with an IW trailer having fitted LED lights. Does any one make a connector box with the resistors in? That way you can plug LED or non-LED rigs in with or without the box? I’ve got a “intelligent relay” box that will do it but I don’t want to break into the vehicles OEM looms nor is there space to fit the resistors in the trailer light units. This way you could just use it when the trailer you are towing needs it………..
 

rob4586

Well-Known Member
Having similar issues with an IW trailer having fitted LED lights. Does any one make a connector box with the resistors in? That way you can plug LED or non-LED rigs in with or without the box? I’ve got a “intelligent relay” box that will do it but I don’t want to break into the vehicles OEM looms nor is there space to fit the resistors in the trailer light units. This way you could just use it when the trailer you are towing needs it………..
I've seen something like this used....but they aren't cheap!

 

nic531

Well-Known Member
my old landy will not accept led unless you leave the side repeaters as normal bulbs... probably a similar issue despite having a new relay with resistor built in.....
 

Eyefor

Well-Known Member
Many thanks for all replies.

After input here (and elsewhere) and a fair amount of googling and phoning of IW etc, inline resistors will be fitted to the trailer.

Thanks again.
 
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