Seat Leon KL1 (2021+) — Tow bar wiring harness Leoni (10R00-10R04-12085 01): complete wiring guide

[Pierreko]

Hi everyone,

I recently installed a Leoni 10R00-10R04-12085 01 wiring harness on my 2021 Seat Leon KL1 and it was a real pain to figure out. The manufacturer documentation is hard to read and the wire color mapping between the vehicle and the Leoni control box is nowhere to be found in a clear format.

After hours of research and no answers from the seller, I put together a wiring guide with full wire-to-wire correspondence (vehicle side vs. Leoni box side), MX3 connector pin assignments, and the relevant pages from the official wiring diagrams.

Hopefully this saves someone else the headache. PDF attached — feel free to use and share.

 

[TVK]

Did ou connect the wireloom from the towbar direcly into the wireloom from the taillights?
I wonder if you get any errorcodes in the car.

 

[East Yorkshire Retrofits]

Did ou connect the wireloom from the towbar direcly into the wireloom from the taillights?
I wonder if you get any errorcodes in the car.

That's the worst possible thing you can do during a towbar installation on a modern car

Warranty issues
Insurance issues (due to improper integration with ADAS systems)
Electrical issues

The car must be made aware it's towing so the relevant ADAS systems can be adapted to suit. The engine must know as it often affects power output. The gearbox must know as it often affects shift points. Lamp load monitoring is closely monitored by the BCM. The list goes on.

By the looks of it, all these problems will likely apply to the OP as there's 0 canbus integration with this kit. I'd highly advise against other people purchasing this kit.

Use a genuine towbar, with a genuine control module & genuine wiring. Warranty safe, looks and works as if factory fit. Buy cheap, buy twice

 

[TVK]

That's the worst possible thing you can do during a towbar installation on a modern car

That's why i'm asking what errorcode's he's got now in the car

 

[Pierreko]

That's why i'm asking what errorcode's he's got now in the car

0 error. It's a dedicated kit and it's exactly the kit that mechanics install. My car's wireloom is analog so there is no impact on the rest. The box just measure the voltage of the wires going to the wireloom and apply the voltage from the battery to the towbar. Some cars has a CAN and in this case, you have to use the proper interface to drive the towbar.

 

[East Yorkshire Retrofits]

0 error. It's a dedicated kit and it's exactly the kit that mechanics install. My car's wireloom is analog so there is no impact on the rest. The box just measure the voltage of the wires going to the wireloom and apply the voltage from the battery to the towbar. Some cars has a CAN and in this case, you have to use the proper interface to drive the towbar.

Your car has canbus... Lots of canbus..

The car has no idea it's towing, your ADAS systems will not work correctly. It's a stone age solution installed on a modern car

This is an awful towbar kit. It's a generic relay kit, not a dedicated kit. Avoid.

Even this is a better solution but it's still not perfect, it emulates a genuine trailer module https://www.westfalia-automotive.co...icle-specific-13-pins-322080300113?m=mod40535