Why do I loose all my rear lights when I plug my trailer in?

[Lee_edwards]

Hi all I have a mk7 ex RAC transit, Iv towed my trailer a good few times this year and even a couple of weeks ago with any issues (other than sometimes the fog light came on the dash when I braked)

Came to use the trailer today and soon as I plug it in none of my rear light work nor do they on the trailer!?

Iv tried a different trailer and it's the same so it must be my van.

I have removed the rear near side light and seen the towing loom... All looks to be in one peice

Thanks lee

[Darren.w]

Is the fuse box still in the back of the van at the side door?? If so there's a fuse in there that needs put it. I had the same problem.

[TripleSix]

On mine the towing relay module was full of water.

I bought a complete new kit and ripped the old one out.

[Lee_edwards]

All the fuses are in that box just inside the door in the side.

[moldavite]

have you put fuses in the fuse box down behind the drivers seat ?

[Lee_edwards]

Turned out to be a dodgy fuse in the fuse box inside the side door. Strange though as the fuse has been in there a while and the lights have always worked.
There wasn't any current coming through the fuse, but the fuse tested ok. Changed it and problem solved!!

Thanks

[Terry]

Hi
I realise you have solved your trailer lights problem, but as info, modern trailer wiring/relays often have a control which switches the towing vehicle's indicators & brake lights off, to cut down reflections that would appear in the rear view mirror if it were a car towing a (usually white) caravan.
Life was simple before electronics were invented
Have fun
Terry