Two years ago i fitted a tow bar with dedicated electrics for the two 7 pin plugs from PF Jones.
Up until recently all has been fine and everything has worked as it should.
Traded the tin tent in and new tin tent has 13 pin plug.
Bought adaptor 2 x7 pin plugs to 13 pin socket from caravan dealer ,and brought my new tin tent home.
On the way back some 10 miles kept getting message flash up check trailer lights

Bought a plug in bulb checker and all is well with new tin tent
Howver when i plug the bulb checker in the car it shows the fog light to be at fault and remains unlit.
I have checked the two fuses 20 and 15 amp, together with the large 50 amp and all seem fine.
The wires are all ok in the socket

Is there anything else i can check?
Do i need a new trailer module
(if so i will be replacing existing with 13 pin socket)
I was hoping to use the tin tent at the BH for the first time next weekend
Any advise would be great cheers

Has your new tin tent got led rear lights ?

No All Bulbs

I had similar issues with the 13 pin to dual 7 pin adapter cable on a Disco 3. Nothing wrong with the cables, or teh car, or indeed the caravan. But the combination of all 3 led to lots of bonging and warnings about bulbs being out. I changed the loom on the car to a 13 pin one (not expensive and is plug and play) and it was all peaceful again.

The main issues were reversing sensors going nuts and fog lights complaining of blown bulbs. The car had been programmed on testbook as well. Bizarre.

Yes mine all worked fine on dual 7 pin plugs for 2 or so years.
Since using the adaptor to 13 pins i now have a error message
I have checked all the caravan bulbs both by taking them out one by one and with a plug in tester.
All is well on caravan side.
However, when i plug the tester into the 7 pin black socket on the tow bar,
it is not lighting the fog light test bulb up
But all the others ie indicators, brake lights rear lights all illuminate on the tester.

As i have mentioned earlier, i have checked all the sockets for loose connections
Checked all the fuses, all looks like it did when if first fit it all.

Maybe i should just buy the full 13 pin wiring kit and hope that it sorts things out.
My other concern is as things are the 7 pin sockets arent testable for the mot
The new 13 pin will be
and if i cant get this sorted out its a failed mot

Well pin 2 of the black 7pin socket is for the fogs. See if it has any power when the fogs are on.
From what you say it won't. Trace it back to the car.

Bingy wrote:

The new 13 pin will be
and if i cant get this sorted out its a failed mot

So i ripped out all the old twin sockets and wiring, together with the towing module.
Replaced with the Westfalia 13 pin one and my fatty is back to being happy again.
As others have said, it must be something in connection with the converters that they dont like.

The only drawback now is i cant use my shared twin wheeled trailer, as it has a single 7 pin plug on.
Looks like i may have to borrow my mates nissan for that

Thanks for all the inputs

You can buy a converter that plugs in to the 13 pin socket and has a 7 pin socket for your trailer.
Around £8.00

Steve. 1968 Series IIA Pastel Green, nearly there project