Horn Wiring and public embarrassment.

[JFerg]

It always used to do it occasionally, but now it does it with a frequency approaching regularity...tooting the horn all by itself when turning.

 

Obviously the wire between the horn push and the horn relay has become damaged and is grounding sometimes where it ought not to be grounding. So I have had a look...and can't for the life of me see where and how it runs. Somewhere there must be a wire that enters the hollow and rotating section of the steering column, and it must be behind the firewall somewhere.

 

Ordinarily I would perform a long sequence of contortions to discover the truth, but in deference to my back, I thought I'd ask the group if anyone could save me the pioneering.

 

So what is thestory there?

 

JFerg

[TR 2100]

The steering column itself is the ground to the chassis (which is

why you need a continuity earth wire through the rubber connectors).

 

The horn push simply connects to the column to ground the horns.

 

There must be a fault in the earthing mechanism in the horn push

area.

Or - maybe there's an intermittent short in the wiring UP TO the

horn push.

 

AlanR

[jerrytr5]

It's usually at the top of the column. If you loosen the retaining bolts for the outer column and move it slightly downwards away from the steering wheel (no more than a couple of mm)that usually does it. If it doesn't, probably needs new column bushes.

If you want to see what's happening and where the horn wire goes, remove the steering wheel (leave nut on after loosening to avoid knocking out your teeth) and take a look at the copper slip ring - as you heave on the wheel the column can touch it and complete the horn circuit. NB: Take care of the 'biro' that connects the horn push with the slip ring - they're easily broken.

Jerry

[AndrewMAshton]

Hello, I have a similar problem that is amongst the long list of repairs and 'improvements' I will be carrying out this winter. In short, when I brake hard the horn sounds, bit of a novelty and slightly amusing at first but thats now worn off so I am going to try and fix, any clues where I should start looking, as always, many thaks for your help, Andrew

[Revolution]

Hello, I have a similar problem that is amongst the long list of repairs and 'improvements' I will be carrying out this winter. In short, when I brake hard the horn sounds, bit of a novelty and slightly amusing at first but thats now worn off so I am going to try and fix, any clues where I should start looking, as always, many thaks for your help, Andrew

 

 

 

My experience is that the steering wheel touches the copper slip ring which causes the horn to sound.

 

There have been previous threads on this but I cut a circular piece of plastic to act as an insulator between the steering wheel and the copper slip ring (suggest piece cut from plastic bottle. problem solved!

Edited December 25, 2010 by Revolution

[MichaelH]

Hi, Had same problem, shown in my case by pressure on the wheel:-sounds the horn, my solution was to loosen the locknut which holds the inner steering column to the outer (just in the bonnet, sort of next to the brake master cylinders) and adjust the steering column boss away from the main steering column) then tighten and the locknut up again (needs allen key/sockets)

[PILKIE]

Hi, Had same problem, shown in my case by pressure on the wheel:-sounds the horn, my solution was to loosen the locknut which holds the inner steering column to the outer (just in the bonnet, sort of next to the brake master cylinders) and adjust the steering column boss away from the main steering column) then tighten and the locknut up again (needs allen key/sockets)

 

 

I had exactly the same when re-assembling my TR6 after its repaint!!

Took a bit of sussing out,but I loosened the clamp above the flexi joint,moved it up a tad and retightened to cure it.

Edited December 27, 2010 by PILKIE

[Vila]

It could be any of the above, but my bet is on the wire inside the steering column.

 

Around 20 years ago I had a similar issue with my 1933 Chevrolet that I have owned for 40 years.

 

Assuming you have original wiring in your car, the horn wire is the purple wire that goes through the wire shield on the bottom of the steering column. You should see the wire just behind the dash on the bottom side of the column, where it goes into the shield. Under the wire shield, near the point where it is closest to the steering wheel, there is a 1/2 inch hole in the bottom of the steering column housing. This is where the wire goes in and runs up next to the rotating part of the steering assembly to the copper slip ring. The insulation can easily wear off after years of turning since there is nothing to hold the wire away from the rotating inner shaft.

 

If you loosen the shield clamp nut/bolt on the top side of the steering column just behind the dash and pull the shield towards the firewall it will expose the hole the wire goes through on the front side of the dash. By moving the wire you may be able to duplicate the problem if this is the issue. The insulation could be worn of where the wire goes through the hole or next to the shaft.

 

My next choice would be the actual horn button. I would remove the horn button first and drive the car to see what happens, since that is easier than working under the dash.

 

My last choice would be to check the copper slip ring assemble, since it is the most difficult part to expose. Requires removing the steering wheel.

 

Vila

[pampa]

I had this horn problem also turned out to be the slipring had broken at some time and was shorting out.

[JFerg]

Thanks for all of the replies and comments.

 

There was about an eighth of an inch of linear play in the steering, in that the wheel could be lifted and dropped within the outer column.

 

Following the comments, I adjusted the clamp just under the bonnet to take that out, and teh problem is solved.

 

Many thanks to all.

 

JFerg.

[Pete R]

I had this problem last year and found it to be a damaged wire just under the brass ring. I would suggest you take the steering wheel off and then carefully bend the tabs back in order to lift out the brass ring. It will still be attached to the cable running inside the column casing which exits out under the dash. In my case the wire was chafing on the column and had worn the insulation so that the inner wire touched the column sounding the horn, when turning the wheel. Either replace the wire, there is a connector under the dash, or add some insulation or tape and make sure it is away from moving parts when you refix the ring.