w123 200 tow electrics, brake - indicators?

[skip rat]

hi question 2

the tow bar electrics seem a little odd, they are factory fit as far as i can tell, i suspect its some kind of USA spec thing, but the indicators light up with the brake lights, they flash when you start indicating,,

i spent ages messing with the little plugs in the boot , but couldn't make any sense of it, is there some kind of special trailer light module that control's it?

not expecting to do much towing but i want to know it will work uk style if needed

 

[Ted]

If the trailer works fine when plugged into another vehicle it is almost certainly the connection between the car socket and car earth.
White wire from the socket iirc.
Is it a seven pin plug/socket?

 

[skip rat]

hi, yes std uk 7 pin, tried caravan and a tailor board both same,

i took 7 pin plug apart and couldn't find any thing wrong,

ill have another look at earth wire

 

[brucemillar]

As Ted says. Most likely an earth problem between the lights and the tow socket. I would just have a good google before pulling it apart though. Merc's & BMW's do have odd design/safety features with some of their tow bar electrics. Could it be that this is meant to operate like this?

It might be worth a read at this?

https://caravanchronicles.com/2014/08/20/why-do-my-sidelights-flash-when-i-indicate/

 

[optimusprime]

Flashing lights after turning each item on would be bad earth. Put some vasaline on the metal part of the bulb as it contacts the outer part of the bulb holders .FROM AN OLD CARAVANER ..

 

[grober]

This might be of interest. If not amenable to an easy fix and you intend some serious towing best to fit or get fitted {by a towbar specialist company} an entirely new set up some older installs are bodged or corroded.
https://www.rexbo.eu/jaeger/electric-kit-towbar-12400005?c=100608&at=625

https://media.rexbo.net/5004/t/pdf/electric-kit-towbar-jaeger-12400005-7.pdf

 

[Ted]

If it is the same with a trailer board, then the problem is with the earth connection to the socket.
Follow the wiring from the socket to the inside of the car, and check where the white wire is (or probably isn't) connected to the body.
There will lie the pot of gold