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TR4/4A Next.....TR4 horn ???

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Alex_McMillin

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Ok, next up, the horn. I'm not sure I fully understand exactly what makes this thing work, or in my case, not work. I have installed a couple of conductor wires to hop over the rubber flex couplings on the steering column, but still no luck. Now, I know both horns work. I can ground them individually and they work. So, here are my questions. Firstly, what is the horn button actually supposed to ground to in order to produced sound? Secondly, is it simply that the contacts I have my conductor wires connected to a not clean enough? Finally, do I need a third conductor wire from the bottom of the steering column to the frame?

Any help, photos, etc. would be much appreciated.

...........Cheers, Alex
 
Alex, the wires would be as follows if you are using a relay, which I believe the 4 has.
At the relay there will be four connectors. You should see on the schematic on the relay cover that two of the connectors have a coil indicated between them. One goes to power, and the other to the horn button (which must touch ground.) It does not matter which side of the coil is + or -.
The other two connectors are for the horn itself. One comes from power and the other goes to the horn. Again, it does not matter which side is which.
You must only be sure to get the coil side and the switch side as above.
Here's how it works. With power going into the coil, when it is grounded, current flows through the coil. This creates a magnetic field. This magnetic field pulls the blade of the switched side together, which completes the circuit from power to the horn. When the horn button is released, the magnetic field collapses and the switch is pulled back open by a spring.
Hope this helps, but if not, let us know.
 
Alex, if your wiring is old or been setting around for a while, it may just be the connectors under the dash, all purple. Pull them apart and clean the bullet and inside. If it turns out you have good ground and power but the relay is bad, before you send off for the new one, remove yours and bend the four taps back on the metal case and the working part will come out in one piece, now you will see a little set of points, use a diamond file or very fine emory cloth to clean them up, shove back in the case and use needle nose to overlap the metal taps back in place. You might want to check is before you put it back. Interesting little buggers, you will need two leads of + and - off the same battery to check it out. Wayne
 
Thanks everyone.

Geo, From where to where does the third ground wire go. I am having trouble determining the best location. Actually, the from is easy enough, but I don't know the best place on the frame to connect the final end.

...........Thanks, Alex
 
Hi Alex,

Not sure if this is "correct", but I added a ground from the brass plug in the steering pinion box (the plug that's removed and replaced with a zerk when lubing the rack & pinion) to the "ear" mount of the steering rack.

My TR4 is a relatively early one, came without this ground. It solved problems with the horn.

I've since added other grounds for the themrostatic fan switch and for the electric fan itself. Photo at https://www.triumphowners.com/640 (look in the Carbs, Engine & More folder).

Cheers!

Alan Myers
San Jose, Calif.
'62 TR4 CT17602L
 
[ QUOTE ]
Not sure if this is "correct", but I added a ground from the brass plug in the steering pinion box... to the "ear" mount of the steering rack.

[/ QUOTE ]

I believe that is correct.
 
Thanks everyone. I now have sound at the push of a button. It's amazing what good clean contacts will do. I took out the entire steering assembly last night, cleaned all the contacts, and re-assembled it. Alan, I did use the plug on the steering pinion box, for the third ground wire, and jumped it to the frame. The photo helped.

Thanks again.

.........Cheers, Alex
 
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