Towing/Towbar electrics

[ColchesterFC]

Due to go away on holiday tomorrow in the caravan so cleaned it all up and plugged in the electrics lead to the car to check the lights. Indicators and headlights work but couldn't get the brake lights to work. Swapped to Mrs Colch's work trailer, which uses a different lead and had exactly the same problem with the brake lights not working but all other lights working. Assumed it was a problem with the car towbar electrics.

Managed to find a garage to look at it and they plugged it into a suitcase type device with lights in it and all the lights worked. Then plugged in a trailer light board and all the lights on that worked as well. I've been to Halfords and picked up another trailer lightboard and everything works on that but still no brake lights on either the caravan or trailer. I know it's not the bulbs as I tried them in the other sockets and they are working and I find it hard to believe that both the caravan and trailer have developed exactly the same fault at exactly the same time.

Any suggestions as to what might be wrong or anything to check to try to fix it? Thanks.

 

[Bunkermagnet]

If I'm reading that right, your trailer brake lights aren't working with either of your trailers?
Have you checked the cables are tight on the car side socket?
It might also be the brake light pin feed, but car electrics can be a nightmare

 

[ColchesterFC]

If I'm reading that right, your trailer brake lights aren't working with either of your trailers?
Have you checked the cables are tight on the car side socket?
It might also be the brake light pin feed, but car electrics can be a nightmare

Correct. Trailer brake lights aren't working on the caravan or Mrs Colch's work trailer, which use different leads to connect to the car. But when I attach a separate trailer light board (got this one from Halfords..... https://www.halfords.com/motoring/t...PpxPqdmNC3_wfwz823T514E68w6TcDncaAp_nEALw_wcB) all lights are working including the brake lights.

 

[ExRabbit]

https://www.etrailer.com/question-161374.html

Might be that there is some corrosion on the sockets which aren't enough to stop it working with new kit, but might with older stuff. Try giving everything a clean.

 

[Bunkermagnet]

Correct. Trailer brake lights aren't working on the caravan or Mrs Colch's work trailer, which use different leads to connect to the car. But when I attach a separate trailer light board (got this one from Halfords..... https://www.halfords.com/motoring/t...PpxPqdmNC3_wfwz823T514E68w6TcDncaAp_nEALw_wcB) all lights are working including the brake lights.

So Mrs C has 13 pin electrics, and the car 7 pin?
Have you checked the adapter lead?

 

[ColchesterFC]

So Mrs C has 13 pin electrics, and the car 7 pin?
Have you checked the adapter lead?

The caravan has 13 pin electric and car has 7 pin so we have an adapter lead for that. Mrs Colch's trailer has a 7 pin fixed lead so no adapter. That's why we thought it was an issue with the car as it's the same problem with two different leads. But the 7 pin on the light board is working fine. All I can think is that some moisture has got into the caravan and trailer electrics while they've not been in use over the winter and is causing the same fault in both.

 

[upsidedown]

Can you swap the brake light wire in the caravan lead with a known working one to eliminate car or trailer?
Had lights issue with my caravan last year and specialist towing bar company found fault in the sender box?? in the car

 

[jim8flog]

Probably a bit late now

WD 40 (better still switch cleaner) in to the socket and the plug and put in and out a few times.

 

[Jimaroid]

I'd avoid all the trial and error and just get a multimeter on it.