What's with the Horn Button

[adrians]

Hi,
Some assistance please !

I've just purchased a new Horn Button for my '81 Spider. The PO had wiring a second button to operate the horn next to the steering column, cutting the Grey - with a black strip wire from the column connector.

So I reconnected the wiring as is should be and hooked up the new button. All worked well ! ! !

Except !

If I lean on or turn the steering wheel the horn goes off ! !

Is this a common fault or is there something weird about the horn and the ground wiring ? ?

Regards

[ventura ace]

Sounds like you found the reason that the previous owner put in a separate horn switch. No, this is not common -- I've never heard of it before. You may need to do a little troubleshooting to diagnose this thing. Depending on what you find, it may be fixable, or you may need to replace the column switch assy or go back to what the previous owner had done.

Here's what I see from Brad Artique's wiring diagrams for your car (http://www.artigue.com/fiat/Pubs/Wiring_1980_1982.pdf): The Grey / Black wire should be hot 12V, and comes from the solenoid that supplies current to the horns. If the Grey / Black wire is grounded, the horns will sound. There should be a White / Black wire to supply the ground path. I'm not sure about the '81, but I imagine it is similar to my earlier spider. The column switch has two protruding fingers that are connected to the 2 wires mentioned above (you may want to verify this: one should be hot 12V and one should be ground). They rub against 2 slip rings on the underside of the steering wheel. The 12V slip ring is connected to a contact ring on the top side of the steering wheel, and the other slip ring is connected to the splined metal hub. The spring under the horn button keeps the horn button away from the hot 12V contact ring. When you push the horn button, it contacts the 12V ring, and completes the circuit to the metal spring that is touching the splined hub, which is the grounded part of the circuit.

Your horn button does have a spring underneath it, right???? Is the spring tweaked, and maybe touching the 12V???

Good luck troubleshooting!

Alvon

[So Cal Mark]

actually this is pretty common. Usually one of the contacts on the combination switch breaks off, and the broken tip makes contact as you turn the wheel. The broken tip may be laying under the wheel also. When you remove the steering wheel, look closely at the contact ring on the bottom of the wheel. I've seen lots of them with cracked or damaged contact rings

[adrians]

Ok,

I'll rip off the wheel and check the contact points, as far as the column switch assembly goes I know it's new only installed in August 07 by the PO, so I'm assuming it's ok.

Regards

[perthling]

I had this issue on my coupe. It was (as indicated above) attributed to one of the two copper-coloured 'tangs' which connect to the ring on the back of the horn assembly having broken off and was randomly touching the contact, making the horn sound. Great for bringing attention to oneself...

[mbouse]

the Brits use a different approach to this assembly. when i attempted to restore the Triumph horn push (the British name for horn button) i discovered why the P.O. had smashed the assembly with a hammer.

the parts had worn down to the point where it made contact every time the wheel was turned.

apparently, P.O. got a little frustrated.


it is repairable. the additional switch under the dash is not necessary.

[So Cal Mark]

with the electrical situation in most Brit cars, smashing the unit with a hammer is the best revenge

[JeremyB]

When I got my Fiat from Shaun (garagemahaul) he told me about this issue. Mine also suffers from it. He too put an inline kill siwtch for the horn. The way he explained it wa sa littel different. Apparently, without the wire being broken, it can still happen. If I remember correctly, the copper wire makes contact with the metal housing around the horn button. After a while, the copper wire gets worn down, due to constant contact. As the wire wears, copper wire dust collects inside the housing. The copper dust will complete the elect. connection, which causes the horn to sound everytime you turn the wheel, or hit a bump. I have the kill switch turned off. But, when I turn my steerign wheel, with the car turned off, I can hear the relay clicking away, trying to sound the horn.
Along those lines, has anyone come up with a way to actually fix this design issue, or is it a replace parts as needed and deal with it type thing? I was toying around wioth the idea of coming up with an alternate horn button, kinda like the ones on the 80 era jags. Push the end of the blinker arm to sound th ehorn.

[crafty]

I have the same issue with my 81. I removed the steering wheel to discover that, as previously discussed, one of the copper tangs was broken. To avoid any further embarrassment I bent the broken tang right out of the way so as to avoid any contact. I am now running hornless!

Am I right in saying that the 'copper tang' set up is part of the entire column assembly? Or is it something that you can purchase seperately??

Cheers,

Glenn

[adrians]

Glenn,
See my posting about a bypass horn button using the purple wire !

Adrian