I can't get my horn button to work.

I have been through everything with a multimeter and have power all the way up to the wire just behind the wheel, circled in orange in the photo below. There is no voltage across the contactor ring.
When the circled wire is shorted to ground the horn sounds. This is as high up the column as I have managed to find power.

Does anybody know what the connection is like between this wire and the contactor ring? Sliding contact? Flexible wire?




I've tried to remove the wheel and even borrowed a puller but it won’t move at all. Is it on a tapered spline? The haynes manual states to remove the nut and give it a firm knock with the heel of your hand. I have bent the thin pulling hooks I made to fit in the slots in the wheel trying and so am confident it has been pulled enough. I'm worried if I make beefier hooks it will bend the wheel.

Below shows the puller. Should this just slide off?




Finally, what is the small part at the bottom of the wheel, circled in green?
It is a plastic outer with a metal shaft which is sprung loaded i.e. when you pull the metal shaft out it springs back in. A brush of some kind?




This problem has occurred since I took the whole column out to replace the brake master cylinder. One problem I thought maybe the wheel has turned too far in relation to the rest of the column as it has not been restricted by the rack as it usually is on the car. Can this be a problem?



Thank you!

Have you checked the small part at the bottom of the wheel for voltage? I don't have a clue since it's a long time since I disassembled the horn, but I would say you're looking at the horn contact. Try shorting it to the ring.

I've checked, there's no voltage on the small part at the bottom - obviously on the central metallic bit.


There is no connection made with the button to the small part at the bottom. It looks to short the contactor ring to the spring sitting on top of the column shaft.

Thanks

My horn did not work following botched replacement of standard wheel by earlier owner.

My garage fitted a push button on centre panel to get it through MOT.

It works in theory; in practice I would never find it in time or be more preoccupied avoiding an accident to look down for a silly little button.

All academic, the horn sounds like a sheep passing wind on a distant hillside so too embarrassed to use it!

I had the same problem after replacing master cylinders as well, it was down to the spacing of the whole steering column. loosen off the nuts and bolts holding it and move it around till the horn contacts work if you know what I mean.

Solution:

As digger58 said, it is to do with the spacing of the column.


The position of the steering wheel and the shaft it is bolted to is fixed in position in the car, it can only rotate, not move axially up and down.

The upper part of the column can slide up and down the shaft and has slotted bolt holes to allow adjustment in the car. Below shows shaft removed from the lower universal joint and slid up in the column housing to show the connections:



The horn button is connected to the column by two sliding contacts, as shown below:





The part circled in green in the original post above is like a carbon brush in a housing but is not a brush. It is a solid plastic cylinder and is the self cancelling mechanism for the indicators. It fits into a hole in a disc which has lugs on to knock the indicator stalk back to neutral. As below:



I was unable to remove the wheel, it must be seized on. Obviously I don't need to any more.


So if you have this problem the procedure is:

1. Assemble everything
2. Loosen the 6 bolts holding the upper column to the dash rail
3. Slide the column up the shaft by pulling it towards you if you are sat in the seat. This joins the contacts between wheel and column
4. Tighten bolts

FWIW, I recently swapped out the stock steering wheel from my 1988 to an earlier year wheel. It's been ages since I work on these cars. At any rate there's a brass washer that goes on behind the main nut. The horn won't work without it. I couldn't quite see it in the image you provided.

I have a 1993 uno 1.4. the horn does not work. i took the steering wheel and removed horn buttton. there are two spade connectors. do these connect to something please help.
peter