VW Urban Fox - 2007 - Horn Wiring Diagram

[chopper_harris]

Good morning Folks

Some months ago, I tried to diagnose a horn failure in our 2007 Urban Fox.

The issue is that I don't have a flow diagram which covers all of the elements - horn push, fuse, relay and the connector blocks.


When the horn push is pressed, I have confimred that there is no 12v on the horn feed wire.
The horn sounds with 12v accross the terminals.

As far as I know, Fuse 41 supplied the Horn/Dual Horn, the fuse is intact.

This is the relay panel - I was advised to look for relay 646, there is no such relay.





I'm not convinced that there is a horn relay on the Fox Urban, I suspect it runs directly from the Onboard Supply Control Unit (J519)
If this is the case, that part of the OSCU has failed.


I got as far as removing the steering column shroud and the steering wheel.








Searching


Searching for Fox wiring brings up a million hits for the 1980's US model, and the Polo 9N schematics/fuse/relay are not the same as the Fox.


What I need is a schematic which covers each of the elements in the horn flow, and how to find the switched earth in the many steering column connectors.


It should be easy enough to run a wire from the column to a new relay, and wire the horn separately to the original loom - I need to know which wires to pick up for the horn push, please.

The MOT is in a couple of weeks, so any useful comments would be gratefully received.


Thanks

Chopps

[Crasher]

Remind me tomorrow and I will post the diagram, I think the horn is through the body control module.

[chopper_harris]

PM sent, but it doesn't show in my 'Sent' folder ?

[Crasher]

I need the VIN, there are two different systems and the change point was December 2006 build.

[chopper_harris]

Thank you

WVWZZZ5ZZ74026661

[Crasher]

Built 12.09.2006 so it is the later system so really there is no point posting the sections of the diagram but I will mail the main document. The horn plate “H” on the wheel is provided with an earth and when the contact is made to the contact ring “H23”, this goes to the air bag coil “F138”, AKA clock spring and then down to the body control computer J519, so in essence when you press the horn, terminal 17 in the BCM plug called T18b just provides an earth contact so in theory if you put an earth to the brown/yellow wire going into T18b/17, the horn should sound.

If not then looking at the horn itself, this is provided with a permanent earth and the power comes out of the BCM at plug T5n on terminal 2 as the usual DIN standard black/yellow wire and in the engine bay it passes through a 12 pin plug at terminal 11 before reaching the horn and this is an obvious area to check. If you apply power to the BCM plug T5n/2 and the horn works, the problem is a faulty body control module.

[chopper_harris]

Thank you - I would appreciate the diagram of the connectors around the steering column asap

[Crasher]

You need to use a diagnostic system to see if the BCM is seeing the horn push command.

[chopper_harris]

This is pointless - you have wasted a week of my time.

I asked for the schematic for the pin-out from the horn push, and that I would pick up that wire to install a stand-alone relay for the horn.

You offered to post the diagrams on Sunday, today is Friday.

Can any other member help, please.

[Crasher]

I emailed you the full basic equipment current flow diagram, if you feel let down by the free service I offer a full refund......