Caravan Lights Issue

[Johnb]

Wonder if anyone can help! Presently in the Pyrenees touring with everything normal until yesterday. Hitched van, ATC did its thing, checked lights and immediately saw that the off-side running lights (front white and side amber markers came on when brake was applied as well as the normal brake lights.
Re-coupled no change.
Will leave until home if necessary since all lights work except we get extras not wanted. If I travel with sidelights on then everything will look normal.
And quick fixes please. Not sure if fault is car or van and no UK tow cars around to hitch and check.
I’m not going to dismantle plug on van or socket on car.
Have multi-meter but not sure how I would use it except to check an unwanted current for lights pin except no idea which pins to check and surprised lights only come on one side of van.
Help appreciated.

 

[birdman101]

If you have an Hairdryer try warming the car 13 pin socket and the caravan 13 pin plug as damp may be the problem.

 

[Mr Plodd]

Symptoms of a dodgy connection on one of the light units. I would suggest you take the bulbs out of the rear lights, clean up the contacts (bulb and socket) and see if that fixes the issue.

 

[ProfJohnL]

With Mr Plodd on this one, its usually the 0v dc connections corroding. Disconnect clean and reassemble a squirt of WD40 can help keep things working for longer.

 

[birdman101]

Symptoms of a dodgy connection on one of the light units. I would suggest you take the bulbs out of the rear lights, clean up the contacts (bulb and socket) and see if that fixes the issue.

I think from his profile they will be sealed LED lights

 

[Woodentop]

Looks like a short between pins 5 and 6 on the caravan plug - 5 is offside running lights. 6 is brake lights.