Tow bar wiring block?

Discussion in 'Electronics' started by SilverSaloon, Apr 4, 2008.

  1. SilverSaloon

    SilverSaloon MB Club Veteran

    Messages:
    7,759
    Joined:
    Mar 16, 2004
    Car:
    1994 W124 E300D Estate, 1985 R107 280SL
    hi

    I went to fit my towbar wiring in yesterday and noticed that there is a little additional wiring block on the left hand side of the car. I think this is for a towbar wiring block to be added in (to save splicing all the wires etc)??? i could be wrong though!

    does anyone know a part number for this? (if it exists!)

    its a 1994 E300D estate W124.

    of course if all else fails i will just splice the wires but it would be good to get the proper block.... although i couldnt see a similar thing on the right hand side so unsure on how that would work.

    the towbar is not an offical MB item by the way, so i am just wiring direct from the towing electric socket direct to the rear lights. As far as i can see the bulb faliure stuff should be sufficient enough for me to avoid fitting a buzzer

    thanks

    Derek
     
    Last edited: Apr 4, 2008
  2. bigshineybike

    bigshineybike Member

    Messages:
    30
    Joined:
    Mar 27, 2008
    Location:
    based Surrey UK
    Car:
    W124 estate W203 320 CDi estate
    Hello, I am starting to try to work out how to wire my '95 deisel w124 estate for a trailer. since you mentioned this socket I have tried to find the same on my car but cannot, there isnt anything shown on the wiring diagram.can you describe where you are looking, ill then have another look at mine. most of the stuff i found in other forums suggests We need to bring some power from the battery to drive a set of relays so as not to upset the bulb failure device. does anyone know of a suitable feed terminating in the boot area that can be tapped to drive the trailer socket?
     
  3. John Kerr

    John Kerr Active Member

    Messages:
    99
    Joined:
    Jan 4, 2007
    Location:
    Folkestone Kent
    Car:
    W209 CLK 220CDI Sport

    You need a bypass relay.this takes a 12 volt feed from a live source and provides the power to the trailer lights,the connections to the vehicle lights serve as triggers for the relay to operate and does not affect the bulb warning.Cost about £20
     
  4. OP
    OP
    SilverSaloon

    SilverSaloon MB Club Veteran

    Messages:
    7,759
    Joined:
    Mar 16, 2004
    Car:
    1994 W124 E300D Estate, 1985 R107 280SL
    hi

    the block i am speaking about is just behind the spare wheel on an estate.

    i decided to just tap into the wiring after this plug.
     
  5. Dieselman

    Dieselman Banned

    Messages:
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    Jul 13, 2003
    Car:
    Peugeot 403 Convertible
    You do need either a warning buzzer or light that operates when the trailer is hooked up and working properly. The bulb warning wont do this.

    As has been mentioned you will also require a bypass relay so you don't cook the original relay and wiring.
     
  6. OP
    OP
    SilverSaloon

    SilverSaloon MB Club Veteran

    Messages:
    7,759
    Joined:
    Mar 16, 2004
    Car:
    1994 W124 E300D Estate, 1985 R107 280SL
    i've just tapped into the existing wiring direct - the bulb failure does come on when the caravan is hooked on but seems fine....

    no buzzer which i know is a bit dodgy but do they really test this on an MOT?
     
  7. bigshineybike

    bigshineybike Member

    Messages:
    30
    Joined:
    Mar 27, 2008
    Location:
    based Surrey UK
    Car:
    W124 estate W203 320 CDi estate
    My biggest problem with this job was in locating a 12v feed. I have used one from the connnector block to the sunroof using a meter you will find one terminal is always live. this has enough power to drive the relays that are described as neccesary to overcome the bulb failure unit.
    Mine works fine now. T
    Thanks for all the advice I was given.
     

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