Mr Lucky

Hi all. I have recently fitted a used genuine Mercedes fold away tow hitch to my 2010 S212 E350 CDI. It came with the electronic tow module and the tow hitch wiring plugs straight in. But I cannot for the life of me see how it connects to the Mercedes wiring harness in the boot (or trunk if you are Stars and Stripes). Oris (the manufacturer for this particular MB branded product) ignore my emails and my MB dealer can see the tow hitch and module on their system but they cannot find any evidence of a wiring harness add-on on their system. The tow module has three sockets and the tow hitch electrics plug into the largest on the left, then as I understand it, there is a red plug from the car wiring harness for the middle and a blue plug for the right. Does anoyone have a similar tow bar or if you know the exact part number I need (or maybe it is hidden in the wiring harness already and I have not noticed it) can you advise?


Tow module with tow hitch connector in left socket. Empty middle and right socket takes a red and blue plug respectively that run somewhere to the car from the module.


A photo culled from the net that shows the coloured plugs that must run to the car.

kajtek1

You are in GB.
FYI US models never come with any tow harnesses or modules, so you have to focus on your country owners.
I did install tow hitches on several MB in USA and for me it is easy.
We do have to use trailer light converters, as US trailers have single lamp for blinker and stop lights, so I am choosing converter with independent power source, to avoid warning lights about bulbs.
Could always find hot wire in the trunk, so job is pretty easy.
From what I read, factory modules, when plug, change transmission shifting points, what helps in towing heavy trailers, but US models do have towing capacity drastically reduced, so with smaller trailer, normal settings work just fine.

Mr Lucky

So is this whole site just USA members then? I'm going to be a bit lost if it is as I don't think they did the W212 diesels over your side.

kajtek1

We do have members from all over the world, but I think over 90% are American.
I recall few UK members, but not in this section, when I know UK does have its own MB forum.
I was drooling about those European hitches, that hide under the bumper with push of the button at driver seat, but even I could import one, that would be not only expensive, but not approved by US DOT. (Dept of Transportation)
We have to have ugly hitch receivers.
Bottom line it is what it is. Good luck on your project.