Trailer lights dim

[Maddog]

Morning all

I recently fitted a tow bar to my van and bought a 2nd hand Trelgo single motorbike trailer so i can drag my bike around when we go away camping.

I noticed when i picked the trailer up that ALL the lights are quite dim. They all work and i have 12.9v at the plug on the van (with the engine running) so i guess the issue is with the trailer. Seeing as it seems to be all the lights that are dim i'm going for a bad earth somewhere, however i cant seem to see a point at which the lights are earthed. Anyone have any ideas where small trailer lights are earthed? incidentally it does have inbuilt lights and i'm not using a light board.

This is the same as mine.

Thanks in advance guys.

 

[Cobbler]

Earthed back through the plug. Pin 3 according to the Diag off the web.

 

[Onoff]

You could perhaps confirm your thoughts by running a temporary, good earth wire direct from the battery. Chassis earth points are always worth looking at, unscrewing, cleaning up and reassembling with a smear of silicone grease.

 

[Migmac]

Corrosion on the terminals in the trailer plug

 

[8ob]

Morning all

I recently fitted a tow bar to my van and bought a 2nd hand Trelgo single motorbike trailer so i can drag my bike around when we go away camping.

Way too many could be's, start from scratch and check the integrity of what you have fitted to your van, plug in someone else's trailer to eliminate that, if there is still a problem move onto the trailer.

Bob

 

[jsf55]

Don't overlook some one fitting 24v bulbs lamps instead of 12v caught me out a few times

 

[Robotstar5]

As above, I'd first check the voltage of the light units. Next, take the plug apart and check the connections followed by sticking 12 volts up the appropiate wires (plug pinout & wire colours are available online)

 

[Maddog]

Someone has been at it before by the looks of it. Plug looks new, but there's obviously been some previous fiddling.

 

[RWD3M]

A quick check might be to hook something else up to your car in case the fault lies there. Nice to be able to rule that out.

 

[Robotstar5]

View attachment 459131

Someone has been at it before by the looks of it. Plug looks new, but there's obviously been some previous fiddling.

Maybe someone swapped from 13 pin to 7 pin plug or vice versa?

 

[colnerov]

Maybe someone swapped from 13 pin to 7 pin plug or vice versa?

Who would do that?


Another one to look for is an earth lead pop riveted to the chassis, I wonder how I know that.

 

[Robotstar5]

Who would do that?


Another one to look for is an earth lead pop riveted to the chassis, I wonder how I know that.

Me!, bought a new trailer with a 13 pin plug, had to fit an adapter to get it home.

Modified the wiring and fitted a 7 pin plug to match my car.

 

[OJCar]

I had one of those Trelgo motorbike trailers for a while.
The connector on the back of the light units had corrosion.
I changed the light units as mine were challenged in other ways as well.

 

[Maddog]

I had one of those Trelgo motorbike trailers for a while.
The connector on the back of the light units had corrosion.
I changed the light units as mine were challenged in other ways as well.

What did you change them for? Same light units again or do you know of any others that will fit?

Cheers

 

[lazybones51]

I have the same trailer but the 2 bike version. The fittings for the light units look the same as mine, so I imagine they're original.

 

[OJCar]

What did you change them for? Same light units again or do you know of any others that will fit?

Cheers

Same light units again.
I can't remember where I got them from, might have been Trailer Tek or e-bay.

 

[Maddog]

Thanks guys.

 

[Turbo]

They all work and i have 12.9v at the plug on the van (with the engine running)

You should have 14.5v unless your van has a smart alternator.

 

[DAPPH]

Corrosion on the terminals in the trailer plug

It's handy to have a trailer plug & socket wire brush cleaning set along with an aerosol of electrical contact cleaner to ensure all the sockets & plug pins are clean .

Way too many could be's, start from scratch and check the integrity of what you have fitted to your van, plug in someone else's trailer to eliminate that, if there is still a problem move onto the trailer.

Bob

Ensuring the trailer is correctly wired up to the plug and all light work before you even bother to plug it into your vehicle ..ensure you have some spare fuses to hand too as it's not unknown for people to miss wire both plug & socket on their vehicle & trailer as a security device , just like I did

View attachment 459131

Someone has been at it before by the looks of it. Plug looks new, but there's obviously been some previous fiddling.

An attempt to stop water ingress in to the plug ..... corroding the connections between copper wires , steel screws and brass pins

 

[Domdom]

Having 12.9v on the van only means at least one of the pins is working. The earth pin is the most important one. Resistance from pin 3 to a good earth on the body is a better test.
Those lamp units earth directly back through the cable, not the trailer chassis.
Don’t rule out corroded internals on the van socket. 7 pin sockets were never good at keeping out moisture.