when connecting a trailer, my indicators go nuts

[anyweb]

hi guys,

when i hook up a trailer to the built in removable tow bar on the car (and corresponding electical port) if i indicate left or right on the car, nothing happens on the trailers lights but my indicator lights on the car blink very fast as they would do if a bulb is blown, my car is a merc C220 1995 version)

so i tried the trailer on our chrysler voyager, no issues at all,

the only difference between my car and the chrysler is i use a 'supplied' adaptor to convert from what i presume is a 15 point 'german' connection to i think it's 9 point swedish standard (i'm no electrician)

long story short, i replaced that connector, and still have the same issue, so how do i go about figuring out what wiring is causing the problem,

points to note:

* the indicators work fine on my car when the 'adaptor' is removed
* the indicators flash fast when the adaptor is connected regardless of whether the trailer is also connected to the other side of the connector or not
* the supplied connector was replaced and the same problem occurs with the replacement

cheers
anyweb

 

[television]

Take them all off, you know the ones that do work, ie brake lights and rear lights. Put them back one wire at a time, testing them after wiring each one. You do need to have the ground connected to do this.

Malcolm

 

[anyweb]

but all my lights already work (unless i connect the adaptor), i was assuming that my issue lies within the wiring of the electrical trailer coupling connector ?

 

[television]

If the trailer is working on the other car, then one assumes that the fault is on the MB, the socket that I was reffering to is the one on the MB. Why not do a search for the wiring, they are all colour coded, and it will tell you what wire is what.

Malcolm

 

[opps-man]

I have the same type of factory fitted tow bar, with a 13 pin connector.
I purchased a 7 pin adaptor from e-bay and this works well.
However if I leave the adaptor connected without the trailer connected then I get the rapid indicators and a bulb failure light.
It sounds like you have a problem with the wireing in the 13 pin socket on your car.
As television suggests the easiest route would be to re-wire the 13 pin socket on you car.
Cheers
Don.

 

[anyweb]

yeah that sounds exactly like my problem,

when you say re-wire it, how should i go about that ? should i completely remove it plus the wire assembly or try another tactic,

any idea what wire does what ? do you have a diagram of the wiring ?

cheers
anyweb

 

[OlafMaxwell]

I have the factory wired towbar and use it with the 13/7 pin adaptor. If I disconnect the trailer the indicators flash very fast. The car senses the socket and powers it up for the extra load from the trailer. However, the adapter is a slittle sensitive, need to make sure it is correctly fitted and locked in position. If not I still get the faster flashing but don't get proper power to the trailer- no power at the bulbs. I think the connectors get a coating from general humidity and need to be wobbled slightly when first connected to clean them off.

 

[television]

Here young man, just for you

http://www.towitall.co.uk/trailer_wiring/instructions.htm


Malcolm

 

[anyweb]

thanks Malcolm,

hopefully i'll get a chance to check this out shortly,

OlafMAxwell, it sounds like you have the same problem as me, can you confirm if the indicators ever flash correctly when no trailer is connected BUT the 13/7 adaptor is connected

cheers
anyweb

 

[OlafMaxwell]

To be clear, when you fit the adaptor but no trailer connector the indicators are powered up and flash like mad. Its not a problem though, it's what its designed to do. You do have to wiggle the conenctions slightly to make sure you have a good electrical connection when you attach the trailer connector.