Alfa Romeo Forums banner

1 - 20 of 21 Posts

·
Registered
Joined
·
44 Posts
Discussion Starter #1
Seeking advice on a horn that blows constantly. Background: I replaced the steering wheel on my 86 GTV6 with an aftermarket similar to a Nardi. Prior to the steering wheel removal the horn was inoperative. With the new wheel, I made a shim for the copper ring to make it extend far enough to touch the horn nub/brush, as described in other posts such as this one:

(Installed Nardi hub & now horn doesn't work
)

I also replaced the ground strap on the steering shaft, the old one had rotted away.

These steps yielded a horn that still didn’t blow at all. After that, I tried replacing the horn relay. Result was a horn blowing! So it’s alive but will not shut off. Horn button was no effect. If I break the connection between the nub/brush and the copper ring, horn stops.

I’m not sure what to look at next-thoughts?

Thanks,
Justin


Sent from my iPhone using Tapatalk
 

·
Administrator
Joined
·
16,807 Posts
There must be a connection ('short circuit') to ground somewhere. For some reason horns are wired 'hot' and the ground connection is switched.

The horn in our Spider once started beeping when I'd let out the clutch to start out from a stop. It turned out the wire that passed through the steering column was a bit too long and when the engine moved a bit on it mounts due to torque reaction as I let out the clutch to start moving the exhaust manifold would contact the wire. It didn't take long for the hot manifold to melt through the insulation and provide the ground connection.
 

·
Registered
Joined
·
29 Posts
Seeking advice on a horn that blows constantly. Background: I replaced the steering wheel on my 86 GTV6 with an aftermarket similar to a Nardi. Prior to the steering wheel removal the horn was inoperative. With the new wheel, I made a shim for the copper ring to make it extend far enough to touch the horn nub/brush, as described in other posts such as this one:

(Installed Nardi hub & now horn doesn't work
)

I also replaced the ground strap on the steering shaft, the old one had rotted away.

These steps yielded a horn that still didn’t blow at all. After that, I tried replacing the horn relay. Result was a horn blowing! So it’s alive but will not shut off. Horn button was no effect. If I break the connection between the nub/brush and the copper ring, horn stops.

I’m not sure what to look at next-thoughts?

Thanks,
Justin


Sent from my iPhone using Tapatalk
If you remove the wiper ring from touching the nub and the horn stops, then your fault is somewhere on the steering wheel assembly, and I suspect that your wiper ring is touching earth somehow in its assembly or that the horn button contact is constantly making contact with the ring. If the fault lay elsewhere, then the horn would still sound even with the wiper ring removed as the short would be somewhere backwards of, or at the nub. Work through the pieces individually using a continuity checker to earth to isolate the continuous ground. Also check that there isn't a floating loose earth wire or other metal component contacting the wiper ring when it's back on the shaft. Good luck
 

·
Registered
Joined
·
66 Posts
If you remove the wiper ring from touching the nub and the horn stops, then your fault is somewhere on the steering wheel assembly, and I suspect that your wiper ring is touching earth somehow in its assembly or that the horn button contact is constantly making contact with the ring. If the fault lay elsewhere, then the horn would still sound even with the wiper ring removed as the short would be somewhere backwards of, or at the nub. Work through the pieces individually using a continuity checker to earth to isolate the continuous ground. Also check that there isn't a floating loose earth wire or other metal component contacting the wiper ring when it's back on the shaft. Good luck
Seeking advice on a horn that blows constantly. Background: I replaced the steering wheel on my 86 GTV6 with an aftermarket similar to a Nardi. Prior to the steering wheel removal the horn was inoperative. With the new wheel, I made a shim for the copper ring to make it extend far enough to touch the horn nub/brush, as described in other posts such as this one:

(Installed Nardi hub & now horn doesn't work
)

I also replaced the ground strap on the steering shaft, the old one had rotted away.

These steps yielded a horn that still didn’t blow at all. After that, I tried replacing the horn relay. Result was a horn blowing! So it’s alive but will not shut off. Horn button was no effect. If I break the connection between the nub/brush and the copper ring, horn stops.

I’m not sure what to look at next-thoughts?

Thanks,
Justin


Sent from my iPhone using Tapatalk
Seeking advice on a horn that blows constantly. Background: I replaced the steering wheel on my 86 GTV6 with an aftermarket similar to a Nardi. Prior to the steering wheel removal the horn was inoperative. With the new wheel, I made a shim for the copper ring to make it extend far enough to touch the horn nub/brush, as described in other posts such as this one:

(Installed Nardi hub & now horn doesn't work
)

I also replaced the ground strap on the steering shaft, the old one had rotted away.

These steps yielded a horn that still didn’t blow at all. After that, I tried replacing the horn relay. Result was a horn blowing! So it’s alive but will not shut off. Horn button was no effect. If I break the connection between the nub/brush and the copper ring, horn stops.

I’m not sure what to look at next-thoughts?

Thanks,
Justin


Sent from my iPhone using Tapatalk
There may be a relay located near your horn that may be stuck on.You might need to replace it.
 

·
Registered
Joined
·
44 Posts
Discussion Starter #5
If you remove the wiper ring from touching the nub and the horn stops, then your fault is somewhere on the steering wheel assembly, and I suspect that your wiper ring is touching earth somehow in its assembly or that the horn button contact is constantly making contact with the ring. If the fault lay elsewhere, then the horn would still sound even with the wiper ring removed as the short would be somewhere backwards of, or at the nub. Work through the pieces individually using a continuity checker to earth to isolate the continuous ground. Also check that there isn't a floating loose earth wire or other metal component contacting the wiper ring when it's back on the shaft. Good luck
Thank you-I’m not sure I’m following this exactly. There is a small ring that seems to control the turn signal return. Is this what you mean? I can’t seem to remove that one.

There is a larger plastic ring with the copper strip around it that is touching the square peg or nub or brush or whatever. My understanding is that this should touch at all times.

I think your theory may be correct; I’m just having a bit of difficulty confirming. For the continuity check to ground, one multimeter probe on the copper ring, the other on the chassis or some other ground component?


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
29 Posts
Thank you-I’m not sure I’m following this exactly. There is a small ring that seems to control the turn signal return. Is this what you mean? I can’t seem to remove that one.

There is a larger plastic ring with the copper strip around it that is touching the square peg or nub or brush or whatever. My understanding is that this should touch at all times.

I think your theory may be correct; I’m just having a bit of difficulty confirming. For the continuity check to ground, one multimeter probe on the copper ring, the other on the chassis or some other ground component?


Sent from my iPhone using Tapatalk
Correct, check continuity to ground between all components in the circuit, starting at the "larger plastic ring with the copper strip" - that is the wiper ring which takes power from the horn circuit at the "nub" to the hooter button or switch, and working your way rearwards to the hooter switch itself. The only exception here is the termination lead of the hooter switch, which must obviously be grounded!
It will be helpful to isolate the individual components too, as if the short is, say in the connector lead between the ring and the hooter switch, then you'll get continuity to ground in all the components remaining in the circuit due to them being of one circuit. I hope I have explained this clearly?
My hunch is that the horn switch is the most likely suspect, with a bent contact etc?
 

·
Registered
Joined
·
44 Posts
Discussion Starter #8
I added a wire to the second terminal of the horn switch and touch that wire to ground to complete the circuit. Now the horn still is in an always on state, but it shuts off when the horn button is depressed! Seems like progress, but not sure how to reverse the polarity. Could this be a faulty horn itself?


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
1,207 Posts
My 2c, having installed a new steering wheel too.
Ok, so you‘ve got the concept that the power supply line which comes up the steering column is ‘always hot’ (continuous power supply), yes, and there shouldn’t be a trail to ground (which is what completes the circuit and allows the horns to sound) until you push the horn button?
You don’t want the power trail to reach the horn button contacts until it is pushed, then you need a trail from horn button to hub/shaft/ground.
My Nardi wheel used a wire from horn contact to hub/ground, the original wheel used metal-to-metal. You’re not connecting the power wire to that wire by any chance, are you? That would mean continuous blow.
Since the horn goes off when you push the horn button, your problem does indeed seem to be at that point rather than relays etc: you are breaking the trail to earth, rather than making it.
You said earlier you’ve added a shim to ensure contact somewhere...that wasn’t between the lower contact and the horn button to make continuous contact was it? Doing that would make the horn stay on too.
Can you trace the power supply from power wire to lower contact ring, to horn button (only when pushed), then to column ground, per manny Kay’s advice?
 

·
Registered
Joined
·
44 Posts
Discussion Starter #10
My 2c, having installed a new steering wheel too.
Ok, so you‘ve got the concept that the power supply line which comes up the steering column is ‘always hot’ (continuous power supply), yes, and there shouldn’t be a trail to ground (which is what completes the circuit and allows the horns to sound) until you push the horn button?
You don’t want the power trail to reach the horn button contacts until it is pushed, then you need a trail from horn button to hub/shaft/ground.
I’m not sure how to change this. I can make sure a wire from the horn button touches ground, or not, but I can’t make the wire move to and from ground when the button is depressed. I assumed this connection is broken/made within the horn button itself.

My Nardi wheel used a wire from horn contact to hub/ground, the original wheel used metal-to-metal. You’re not connecting the power wire to that wire by any chance, are you? That would mean continuous blow.
Not exactly sure what you mean. the power wire, meaning the wire coming up from the steering column/fuse box, is connected to a terminal on the horn button. The second terminal on the horn button is connecting to a short wire I made that reaches out and touches the hub/ground.

Since the horn goes off when you push the horn button, your problem does indeed seem to be at that point rather than relays etc: you are breaking the trail to earth, rather than making it.
You said earlier you’ve added a shim to ensure contact somewhere...that wasn’t between the lower contact and the horn button to make continuous contact was it? Doing that would make the horn stay on too.
Can you trace the power supply from power wire to lower contact ring, to horn button (only when pushed), then to column ground, per manny Kay’s advice?
My shim makes it so that the copper ring touches the square nub, continuously. My understanding g is that this is how it should work? If they do not touch, pushing the horn button will have no effect at all. I’m trying to trace power supply through each point but must not be doing it correctly. I can trace power making it to the horn itself...


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
1,207 Posts
Sorry if I wasn’t clear, but my point was that you don’t want a continuous chain of power to get from that steering column wire to earth until the horn button is pushed. It’s a matter of careful observation to see how the horn operates and follow that power chain.

It has been while since I have had an Alfetta, so I can’t picture the original setup, much less a modified one.

You did also say “I added a wire to the second terminal of the horn switch and touch that wire to ground to complete the circuit.” you may have inadvertently powered both sides of the button mechanism. I’m a little surprised you had to add any extra wiring. What happens if you disconnect that?

Lastly, does the wheel manufacturer provide any guidance?

I also did a quick search “Nardi horn button wiring” and got heaps of pictures/results. worth a look.
 

·
Registered
Joined
·
29 Posts
Here's a simple diagram of how the horn circuit normally works. As seen, power runs through the relay coil, through the wiper nub/brush, which is in constant contact with the wiper ring and is open circuited at the horn button or switch. When closed or depressed, the button completes the circuit, energising the relay coil which switches power to the horn. I have a very strong feeling your problem has to lie between the wiper ring and the horn switch, where one of these components and its associated terminals, wires etc. is causing a continuous closed circuit to ground, thereby energising the relay and sounding the horn...
You will need to do a continuity check with a meter or lamp to source the faulty line to ground. trust this helps
horn circuit.jpg
 

·
Registered
Joined
·
44 Posts
Discussion Starter #13
Thanks all, this saga continues. When I remove the wheel and the wiper ring altogether, so the nub is touching nothing, horn does not stop blowing. So this indicates the issue is not at the wheel assembly, but rather somewhere before the hub/wheel, correct? (E g st the fuse box or somewhere between the steering hub and the horn). D

I also removed the ground wire that jumps over the steering shaft knuckle. This also had no effect, the horn keeps blowing.

Continuity testing has been an ongoing challenge. If I connect the horn,it is too loud to do any kind of testing due to neighborhood disturbance. I don’t have a test light available but I have a multimeter. I don’t get any readings when the horn is disconnected.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
29 Posts
Thanks all, this saga continues. When I remove the wheel and the wiper ring altogether, so the nub is touching nothing, horn does not stop blowing. So this indicates the issue is not at the wheel assembly, but rather somewhere before the hub/wheel, correct? (E g st the fuse box or somewhere between the steering hub and the horn). D

I also removed the ground wire that jumps over the steering shaft knuckle. This also had no effect, the horn keeps blowing.

Continuity testing has been an ongoing challenge. If I connect the horn,it is too loud to do any kind of testing due to neighborhood disturbance. I don’t have a test light available but I have a multimeter. I don’t get any readings when the horn is disconnected.


Sent from my iPhone using Tapatalk
Yes, your fault lies somewhere south of the wiper ring. You will need to trace backwards until you find where the short circuit occurs. Your fault is potentially very simple and quick to fix - however, trying to describe how to find the fault is another matter without your vehicle to hand.
A test lamp is simply a 12v globe with 2 leads - you can easily make one yourself or buy one at an auto parts supplier. If you can't trace the wire for whatever reason, your quickest solution will be to run a new power feed to the horn wiper ring.
Also, first remove the relay which feeds the horn if your vehicle has one, and replace it with a substitute to check that the contacts aren't welded together. This can and does occur on occasion and will prove a major headache if you don't eliminate it as a potential source of your failure...
 

·
Registered
Joined
·
44 Posts
Discussion Starter #16
Also, first remove the relay which feeds the horn if your vehicle has one, and replace it with a substitute to check that the contacts aren't welded together. This can and does occur on occasion and will prove a major headache if you don't eliminate it as a potential source of your failure...
Thanks Manny Kay. I will continue to work on this. I am using a brand new relay so I can rule this last bit out.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
44 Posts
Discussion Starter #17
If one horn fails, this should not necessarily affect the other, correct? I have studied the wiring diagram and they do not appear to be wired in any sort of series but just want to rule that out as my left horn is completely dead; the right horn at least has been shown to make some sound.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
29 Posts
Your horns are connected in parallel, therefore if one fails then the other will still work. Also looking at the pic, I'd say that this is not the source of your fault. Looks to me like like that wire cannot reach ground and thereby cause a short circuit...
 

·
Registered
Joined
·
44 Posts
Discussion Starter #20
You are correct. I went through as much of the wiring as possible today and still no luck. The only areas I have not inspected are firmly shrouded in electrical tape harnessed up and running through inaccessible areas. Ugh!

Right horn wire gets powered all the time unless horn button is depressed while second wire from horn button is touching ground.
Left horn wire gets no power at all.
 
1 - 20 of 21 Posts
Top