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Discussion Starter #1
Hey VW people,

New caretaker of my wife's new 87 cabriolet (built on the MK1 platform). I need to get it inspected and the horn has to work.

Here is the rundown.

Fuse is good
Relay is operational
Horns work when powerprobed
(Removed cover on steering wheel)
Have continuity in horn buttons when used
Have continuity between horn buttons and relay
Have continuity between relay and horns
Have power at relay


Steering column does not have a ground.
When I run a jumper between the column ground horn button wire, and the negative side of the battery terminal, the horns work as intended.

Is there a specific wire that grounds the column itself? If so then where is it located?

Thank you.
 

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The wire that grounds the column, or the inner shaft is on the firewall engine side of the car.
It is usually on the drivers side Power Steering Rack mounting bracket, to the Steering Gear Box case cover.

Don't have the Picture of the GEAR BOX screw, sorry.

Dang almost forgot, on the back side of the steering wheel there is the copper finger on the Turns that scrapes the back side of the wheel to make contact ground. This finger can get bent out of place or break.



There are 2 grounds on the Steering column.
One on the outer steering shaft.
One on the inner shaft.
The inner shaft is what provides the ground for the Horn switches.
The inner shaft is grounded via the Steering gearbox, and the steering rack mount bracket.

Basic circuit of the horn.
 

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Moved your post to the older mk1 platform, more folks will see it here and respond.
 

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Discussion Starter #4
Thanks for the diagram and help. My Chilton's manual showed nothing of the horn, or a good diagram. I found an answer on another forum that just said "check ground on firewall".

I did find the wire that is about 3 in Long and was disconnected. Tested it for ground and eventually found the screw hole on the rack gear box. Had to retap it with a #8 machine screw. Horn started working.

Was concerned with a contact ring issue. Glad that wasn't it.

Passed inspection and is now a Texas resident.

Even went back in the manual and looked at the directions for removing the rack. Said nothing of that wire.
 

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Thanks for the diagram and help. My Chilton's manual showed nothing of the horn, or a good diagram. I found an answer on another forum that just said "check ground on firewall".
Even went back in the manual and looked at the directions for removing the rack. Said nothing of that wire.
The Chiltons is good for the little house down the path in the back :)
Get the a Bentley, or a Haynes, they have more complete diagrams for the wiring. (I have a Chiltons, but I never use it at all.)

You can get them cheap on epay or amazon, usually.....new they are like 60 bucks.
When my binding broke on my Bentley, I put all the pages in plastic sleeves and in a 6 inch binder. (I also took the separated pages into work and scanned them in digitally and assembled them in a PDF by chapter.. :) I know there are digital versions out there....

When Moses was buying a Cabriolet, He got a third tablet.


I redrew my crappy drawing to include the slip ring finger arm in the circuit.
 

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Discussion Starter #6
That's great. I do have that manual for my Aircoolers (and the Muir bible).

Will look for one.

Funny about the page protectors. I did that with my high AF Cummin's manuals. Was planning on doing that with the Chilton. May wait until I have the Haynes.
 

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That's great. I do have that manual for my Aircoolers (and the Muir bible).

Will look for one.

Funny about the page protectors..... Was planning on doing that with the Chilton.
Best thing you can do is to use the Chiltons as a Fire-Starter... :)

Sealy did a how to keep your Rabbit alive, wanted to buy one years ago as I love the drawings, but never did.
Now they are I thought being re-printed....

But you won't go wrong with the Bentley.

In the DIY section I have a bunch of how do I do thats all 90 Cabriolet/automatic based.....so you might also want to check out www.cabby-info.com
 

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You can ground the column any way you like. There is no specific
area. If you can find a bolt or screw on the column, wire to an
eyelet, place it under the bolt or screw, then ground the other end
of that wire to any chassis ground, or right to the (-) battery terminal.
 

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You can ground the column any way you like. There is no specific
area. If you can find a bolt or screw on the column, wire to an
eyelet, place it under the bolt or screw, then ground the other end
of that wire to any chassis ground, or right to the (-) battery terminal.
Yes/No.
Yes, you can ground the outer shaft to anywhere you like. Matter of fact VW has a separate ground on the outer shaft and it still won't work the horn. As a small side note the heater blower motor is usually grounded to the outer shaft.

No, I have found over the years, that you have to ground the center shaft and the easiest is the GEAR BOX.
Yes you could ground the center shaft from inside the car with a wiper spring, or a spring and wire arrangement that slides on the shaft, but the gearbox is best for the horn.
 

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That was one of the many reasons people put a separate horn button in their
cars, those big 1.5" round cream colored push buttons.

Ground the gear box to one of the strut-tower bolts...
 

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Thanks for the info. Have an 87 16v scirocco which I have to get tagged in Texas and after sitting for a year my horn does not work. used contact cleaner on the horn contacts. I can hear the relay clicking when horn buttons are depressed. multimeter shows no power to horn when buttons are depressed. so something is not working from relay to horn. did swap out horn relay with my 88 Fox and no go. so I don't think it is a relay issue. going to hook horn directly to battery to test them. Need to dig around tomorrow when the sun is out to see if I can find the ground wire on the steering rack.
 

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Whenever I have had a horn problem the first thing I do is pull it out and do a direct connect to the battery. It is the easiest to do and if it fails I don't spend a lot of time tearing into the steering wheel parts or the relay tests.
 

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Ground cable was fine after cleaning out grease and muck. found it to be intact... Finally discovered in a 16v scirocco, there are 2 fuses for the horn, spot 16 and 18.
Had replaced 18 initially, once replaced 16... horn worked again.. all weekend... Guess the firewall got a good cleaning i guess.
 

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Two fuses? Why would they do that? One for the horn and one for the relay perhaps? Dual horns on that model?
 

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I have never seen 2 fuses on a horn. I do know that Euro Golfs/Cabriolets the Germans used a solid power to the horn, and used the relay to switch grounds.

The Westy's (mericans) used a solid ground to the horn and Switched 12V.

But there are 2 fuses on Scirocco one that powers the horn f16, and one that powers the relay f18. f18 also powers the oil temp gauge, just looked at the schematics.
 
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