horn wiring in wheel?

Maintenance advice to keep your Spider in shape.
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minimike
Posts: 257
Joined: Sat Apr 10, 2010 7:14 pm
Your car is a: 1979 124 spyder

horn wiring in wheel?

Post by minimike »

It appears after removing my horn push button, that there's a black wire which when the horn button is pushed,
makes a complete circuit by grounding to the inner rim of the wheel. The black wire that connects to the horn inside,
is not hot and I believe it should be.
Where does that wire go after it ends above the turn signal cancelling ring?
I can't find anything in my book or looking at it.
mike
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124JOE
Posts: 3141
Joined: Fri Jun 24, 2011 7:11 pm
Your car is a: 1978 124 fiat spider sport 1800
Location: SO. WI

Re: horn wiring in wheel?

Post by 124JOE »

theres a purple wire "from the relay pannel i beleve theres a yellow wire too on the horn relay"
i by passed mine at the pannel and reconnected just before the plug for the steering colum.
because of a short.

yes its a live wire.well it was.joe
when you do everything correct people arent sure youve done anything at all (futurama)
ul1joe@yahoo.com 124joe@gmail.com
minimike
Posts: 257
Joined: Sat Apr 10, 2010 7:14 pm
Your car is a: 1979 124 spyder

Re: horn wiring in wheel?

Post by minimike »

Joe,
I've got a black wire under the horn push. There's a black wire (top left) in the large harness plug coming from/going to the key switch (ignition). The black wire is hot at the harness plug.
I'm wondering what I need to get juice up to the horn push. There has to be a hot lead that is on the lower side of the column below the turn signal cancelling ring.
Did you run a new wire from the relay to the horn push? If so, how did you get it up the column?
mike
TX82FIAT
Posts: 1814
Joined: Mon May 03, 2010 11:04 am
Your car is a: 82 Fiat Spider 2000 CSO
Location: San Antonio

Re: horn wiring in wheel?

Post by TX82FIAT »

Minimike, Have you taken the steering wheel off and inspected the hub assembly. There are two spring like copper pieces that extend down from the hub under the steering wheel to a copper ring. If you have not taken the hub off already you will understand as soon as you remove the steering wheel. These copper pieces wear out and stop conductance from occuring through the hub. When this happens the black wire under the horn has no juice. Removing the wheel is very easy just take off the large nut under the horn button and jiggle the wheel off. You "do not" need to unhook the wheel from the hub using the six allen bolts. Leave that together for leverage to remove the wheel. This is a common failure point as the copper wears every time you turn the wheel. Literally takes five minutes to take the wheel off with the hub attached and inspect.

If you have already taken the wheel off, inspected the contact points on the hub and determined the problem is upstream from there than start testing the other wires. As a sidenote, I think the horn and the cooling fan are on the same circuit. If your fan comes on at temperature your circuit is most likely good. Two spider, two horn failures at contact points under the hub.
Buon giro a tutti! - enjoy the ride!

82 Fiat Spider 2000
03 BMW M3
07 Chevy Suburban
User avatar
124JOE
Posts: 3141
Joined: Fri Jun 24, 2011 7:11 pm
Your car is a: 1978 124 fiat spider sport 1800
Location: SO. WI

Re: horn wiring in wheel?

Post by 124JOE »

my short was in the dash like behind the radio
so my colum was ok,i didnt have pos
i had a neg reading at the horn and my bypass fixed it
when you do everything correct people arent sure youve done anything at all (futurama)
ul1joe@yahoo.com 124joe@gmail.com
TX82FIAT
Posts: 1814
Joined: Mon May 03, 2010 11:04 am
Your car is a: 82 Fiat Spider 2000 CSO
Location: San Antonio

Re: horn wiring in wheel?

Post by TX82FIAT »

Joe, i think that is one of the fun things about these cars. There is what folks tell you typically goes wrong and then there is what goes wrong on the car you actually own. I've had those shorts under the dash as well. Ownership has its priviledges!!
Buon giro a tutti! - enjoy the ride!

82 Fiat Spider 2000
03 BMW M3
07 Chevy Suburban
minimike
Posts: 257
Joined: Sat Apr 10, 2010 7:14 pm
Your car is a: 1979 124 spyder

Re: horn wiring in wheel?

Post by minimike »

are the brass spring washers? available or do I just stretch what's there? I'll pull the wheel tomorrow.
Mike


Sorry all for not posting this in 'electrical'. Maybe it can get moved by our Moderator.
TX82FIAT
Posts: 1814
Joined: Mon May 03, 2010 11:04 am
Your car is a: 82 Fiat Spider 2000 CSO
Location: San Antonio

Re: horn wiring in wheel?

Post by TX82FIAT »

Mike, it depends on the condition of the two copper prongs that make contact with the ring. Sometimes a good cleaning and pulling the prongs up to make better contact with some dialectric grease will work well. The prongs wear out and the contact points get corroded. You may be able to fabricate something that will work. If that is the issue you can also order a new Column switch for $80/$90 dollars.
Buon giro a tutti! - enjoy the ride!

82 Fiat Spider 2000
03 BMW M3
07 Chevy Suburban
minimike
Posts: 257
Joined: Sat Apr 10, 2010 7:14 pm
Your car is a: 1979 124 spyder

Re: horn wiring in wheel?

Post by minimike »

I pulled the steering wheel to reveal the brass contact ring under the wheel. It had a huge divet in it, thus loss of contact with
the ring. And it was heavily grooved. I'll search around used parts to see if I can locate something better, or may fabricate
another brass ring and install that. Also one of the two copper swipe contacts that touch the brass ring was distorted. It was
bent over the wrong way. (folded) When I tried to fold it back, of course it snapped. I've lifted this contact to see if it
will touch the brass ring, but won't know until I replace the ring.
Thanks for all the help guys. This is indeed a great resource.
TX82FIAT
Posts: 1814
Joined: Mon May 03, 2010 11:04 am
Your car is a: 82 Fiat Spider 2000 CSO
Location: San Antonio

Re: horn wiring in wheel?

Post by TX82FIAT »

Most likely the piece that folded over created the grove in the ring. You may need a new/used hub and a new/used column if you want to retain orignal look and function. Not sure what your end goal is but you may want to now consider a bypass circuit with a button in an easy to get to location to act as the horn. I know it is not the same as having an active horn on the wheel but any fabricated solution will need to have a good amount of engineering to ensure it is smooth, is the right size for the assembly and can withstand the friction of the wheel turning over time.
Buon giro a tutti! - enjoy the ride!

82 Fiat Spider 2000
03 BMW M3
07 Chevy Suburban
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