[TR] TR4A horn

[Carl Sereda]

Hi,
I think there is a misunderstanding of how the TR4 and TR4A horn contacts work.
The steering shaft is the ground.
The flat brass ring is what the telescopic spring loaded contact rides on while pushing against the horn button brass contact.
The two silver colored tags shown in your photograph are simply there to secure the non-conductive base, for the brass ring, which is wired to he horns.
Regards,
Carl
'63TR4 since '74


Subject: Re: [TR] TR4A horn

Eureka!  That?s it.  Just tried it and it works.  Now, how do I fix it?

John

On Jul 12, 2018, at 7:35 PM, Greg <greg at gregoryd.com> wrote:

I?ll add my experience to the mix: the horn on my ?67 TR4A would not work consistently. It would work, but randomly, it seemed. I examined all of the things Dave mentions, tested the wiring, and replaced the relay and the fuse. None of it worked.

The issue ended up being with the contacts pictured below (and here: https://imgur.com/n5mieHF), which bring the circuit up to the steering wheel and from there to the horn push:

<image001.png>

Over the years, these contacts had worn down to the point that the steering wheel did not make constant contact with one or the other. 

I discovered that, if I pushed on the horn and also pushed the steering wheel laterally just a bit to the left towards the driver?s door, or to the right towards the passenger door, contact would be made and the horn would sound. And it worked consistently ? it still does.

If nothing else is fixing it, try the left or right push. Having the engine on helps.

I?ll take this opportunity to ask my own question: does anyone have a recommendation for how to improve the contact ?permanently??  Something like a silver conductive epoxy? If the contacts were maybe a millimeter larger in the direction of the steering column, the left/right push probably wouldn?t be necessary.

One other thing: sometimes the circuit would complete ? you could see it on the ammeter, but still no horn. That took a turn or two on the adjustment screws on each of the horns.

--Greg
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/triumphs/attachments/20180714/73da0c9d/attachment.html>