w203 Trailer Wiring Question

[jerk_chicken]

Sorry, but I'm new to the forum and to MB, after migrating over from Audi (with positive experiences).

I just bought a low mileage 2000 C200k sedan and we're going to be installing a trailer hitch. While the hitch doesn't scare me so much, I am concerned about the wiring and how to ensure it's done right and not with those taps that cut into the wiring, leaving damaged wires that corrode and a host of other electical gremlins. I once had to rewire the whole tail end of a car I purchased because of the damage from the wiretaps.

What is the advice on what parts to make sure the local mechanic (in Germany) does the job correctly? Is there already a tap somewhere for a harness? Is there an intermediate light controller/module that needs to be purchased?

 

[colechelle]

many ways tow bars are fitted now days but i belive the 203 is wired stright into the rear sam, im sure someone on here will correct me or agree!!!!

 

[Aussie Nick]

Wire taps always vulnerable to moisture penetration and loosening due to vibration. Better to cut join and solder. Once soldering complete Seal individual wires with Nitto tape and then heat shrink wrap collar over all wires.

 

[television]

many ways tow bars are fitted now days but i belive the 203 is wired stright into the rear sam, im sure someone on here will correct me or agree!!!!

I can try and check on this

 

[colechelle]

any luck malc, for got to check today???

 

[television]

any luck malc, for got to check today???

I have had a good look on WIS but I cant find "tow bar" for 203, any idea what its under

 

[colechelle]

54 electrics!!

 

[television]

54 electrics!!

I will take a look

 

[television]

Yes it all comes from the rear N10/2 control unit

There should be a lead X68 and 13 pin tow socket that plugs in somehow.

All of the turn signals, lights and brake lamps are on the rerar SAM N10

 

[colechelle]

Nice one malc, lets hope after all your hard work ( and slight input from me) that answers his question, good team work again!!!!!

 

[television]

Any time if you ever want a print out just ask up to 06

 

[colechelle]

thanks as always malc, got the lastest at work, so goes both ways!!!!

 

[television]

thanks as always malc, got the lastest at work, so goes both ways!!!!

Yes I know you, what I should have said was that if you are dealing with a fault here and the OP could use a print out, I can Email direct now from a memory stick, plus I have over 200 in store already plus 100 good links with photos for popular faults,,I must do something with those for when I snuff it they will all be wasted

 

[colechelle]

well i can always pass them along malc!!!!!

 

[television]

well i can always pass them along malc!!!!!

I will leave you my hard drive in my will

 

[colechelle]

well you keep hold of them for many years from now ah!!!!

 

[No1Vic]

Trailer wiring how to....Well how I did it!

Like most on here I had concerns messing with the 'sensitive' vehicle wiring so this is how I did my trailer socket install. Using a H52 smart 7 way bypass relay which came with straight forward instructions for connection to the 12N socket and tapping into the rear light cluster bulb feeds. The relay has screw terminals for the socket wiring and a reasonable length of colour coded cables for tapping into the vehicle lighting loom, which as it they are only to sense a voltage applied to the light in use they have no effect on the bulb monitoring system. For the power supply to the relay and after some research I was pleased to find the rear sam unit already has a point for it. For anyone that doesn't know its location here you go, in the boot and to the left you will see a panel in the carpet that can be pulled out, behind this is a piece of polystyrene which protects the rear sam unit. Pull this out to reveal the fuses and relays. Now if you look to the bottom of the row of fuses there's a block of either four empty fuse holders or four spade terminal sockets. Numbered 20-19-18-17, the feed we need is number 17, a permanent 12v supply at 20amps, I used a spade terminal to connect to the H52 relay via an inline fused lead. Out of interest for anyone wanting to wire a 12S socket too, feed 18 is used for 12v 20amps but switched with the ignition. I tidied the wiring up put the carpet and panels I'd removed back. Plugged the trailer in and everything worked fine, no errors or warnings
I hope this is help to anyone who fancies trying a DIY install.

 

[colechelle]

good info, should help a few owners out and sounds a safe way to install!!!