DIY Horn Upgrade Mod - Updated Jan 12

[TonyWilliams]

I just ordered a Stebel Nautilus Compact Tuning Horn. According to the wiring diagram, in the LEAF service manual, there is a horn relay already there.

Do I need to install a different relay or will the original work?

Please run the correct size wire and (supplied with the horn) relay !!

You don't need to take out the factory relay (it's in the black box directly in front of the 12v lead/acid battery) or the 10 amp fuse. Just use that circuit to operate the 30 amp relay that will operate the Stebel horn.

Run a 12 gauge wire from your power source to the 30 amp relay, then on to the horn. Use the existing 10 amp fuse / relay / wire to trigger the 30 amp relay. Add a 30 amp fuse. Done. Simple.

 

[hatuey]

Please run the correct size wire and (supplied with the horn) relay !!

You don't need to take out the factory relay (it's in the black box directly in front of the 12v lead/acid battery or the 10 amp fuse. Just use that circuit to operate the 30 amp relay that will operate the Stebel horn.

Run a 12 gauge wire from your power source to the 30 amp relay, then on to the horn. Use the existing 10 amp fuse / relay / wire to trigger the 30 amp relay. Add a 30 amp fuse. Done. Simple.

Thanks Tony, I will follow your advice...

ELECTRIC - Bragging Rights!

 

[aqn]

I just ordered a Stebel Nautilus Compact Tuning Horn. According to the wiring diagram, in the LEAF service manual, there is a horn relay already there.

Do I need to install a different relay or will the original work?

When you receive the Stebel horn, you'll find a warning that clearly says that the horn uses almost 20A and requires its own 30A relay, or else you'll risk ruining your horn switch and possibly ignite the wiring if you use the smaller factory relay.

"Ignite the wiring"? Does the warning really say that? I'm not an EE, but I know enough to suspect that a few short bursts through the horn wiring would just barely warm it up i.e. no worries about anything burning up unless one leans on the horn for, say, ten minutes. With a horn such has the Stebel Nautilus, if one blasts it for ten minutes I suspect one would have more serious problems to deal with than burned wirings!

Would a 18A draw (what the Nautilus Compact draws at 12V) over a 10A fuse burn up the fuse? I kinda suspect not, but like I said, I'm not an EE. I think the worst that would happen if one uses the stock relay is that the Stebel won't perform at its peak, not being able to draw the kind of power that it needs.

The Nissan factory relay is only rated at 10A, so it won't be adequate to carry the 20A load the Stebel horn will require for sure. The load of the old horn will be utilized as the switch for the Stebel 30A relay.

This is true.

 

[Volusiano]

I just ordered a Stebel Nautilus Compact Tuning Horn. According to the wiring diagram, in the LEAF service manual, there is a horn relay already there.

Do I need to install a different relay or will the original work?

When you receive the Stebel horn, you'll find a warning that clearly says that the horn uses almost 20A and requires its own 30A relay, or else you'll risk ruining your horn switch and possibly ignite the wiring if you use the smaller factory relay.

"Ignite the wiring"? Does the warning really say that? I'm not an EE, but I know enough to suspect that a few short bursts through the horn wiring would just barely warm it up i.e. no worries about anything burning up unless one leans on the horn for, say, ten minutes. With a horn such has the Stebel Nautilus, if one blasts it for ten minutes I suspect one would have more serious problems to deal with than burned wirings!

Would a 18A draw (what the Nautilus Compact draws at 12V) over a 10A fuse burn up the fuse? I kinda suspect not, but like I said, I'm not an EE. I think the worst that would happen if one uses the stock relay is that the Stebel won't perform at its peak, not being able to draw the kind of power that it needs.

I'm thinking the reason they say it might ignite the wiring is because of the possibility of sparks that may be created if the under-power factory relay is used.

The warning card has a red DANGER sign with a triangle and ! inside (universal sign for danger), and it says the following verbatim:

"This horn uses almost 20 amps of power. Most factory wiring and horn switches are design for much less power. If you install this horn without the enclosed 30A relay and without a HEAVY-DUTY wiring kit & 20A fuse, you will destroy your existing horn switch and may ignite your wiring. Amanet will not warranty such damage, and is not liable for any injury or damage which may result from such an installation."

I think the $20 Plug-n-Play wiring harness model # SNPNP for the Stebel Nautilus Compact Air Horn is not a bad option to buy for convenience, and also to make sure you have the right wire size for the job. It has a heavy duty 40A relay (instead of the included 30A relay that comes with the horn), a 30A fuse, and 18 ft total of #14 & 18 wiring, along with insulated terminals, protective sheath and zip ties. So you don't have to run around buying all the necessary parts yourself.

 

[thankyouOB]

I am a complete electric novice.
you guys scared me off of trying this modification with the talk of 20 amp and 30 amp relays and fire and such.
i thought you could just pull the old horn and replace it with the new one, going either topside or bottomside, depending on availability of ramps to access the underside.

 

[Coffee_Slurry]

It's really simple...

The stock (already in your car) relay and fuse allows up to 10A draw for the horn.

IF your replacement horn also draws 10A or less, you're golden. Yank the stock beeper, put in your own, done.

If your replacement horn draws more than 10A, you will first blow the 10A horn fuse. The horn will not run at "reduced power", it will draw more than 10A and quickly blow the fuse, exactly as designed!

Depending on how risk-averse you are, you could consider increasing the horn fuse rating beyond 10A. Maybe 15A. You would have to convince yourself that the stock relay, connectors, and wiring would be fine for 15A draw without overheating or melting. (If it was me, I'd check all the wire gauges and connectors and see if there are other applications in the car that already use them for >10A.)

Note that there is no risk to your Horn Button in the wheel -- it doesn't carry the current. The horn button just switches the stock relay.

So, if you want to run a 20A horn off your 10A fuse circuit, your best bet is to use the existing power to switch.. another relay. A beefy one with bigger wires, and a bigger fuse going straight to the battery. That's the safe & sane thing to do, and it's really not that much extra hassle. Just another relay and wire run to the 12v battery. Then you can run 50A air horns, semaphore flags, and a strobe light.

 

[Volusiano]

All what Groundloop said is right. It's simple if you understand the requirements.

I would assume that the reason the factory horn sounds dinky and tiny in the first place is because it doesn't have enough power to make it loud enough. So when you upgrade to a louder horn, it's almost a given that you'd expect to be drawing more current to get the increased volume. But maybe I'm wrong and there are other horns designed for only 10A draw that can sound much louder than the stock horn. I'd like to know if anybody has been able to find such a horn.

I looked up the Fiam 74100 El Grande Twin Horns that seem to be popular on this thread for its low price of $16.57 on Amazon, and I notice that it also comes with its own relay. It's not clear on its spec what kind of current it draws, however.

 

[hatuey]

It's really simple...

The stock (already in your car) relay and fuse allows up to 10A draw for the horn.

IF your replacement horn also draws 10A or less, you're golden. Yank the stock beeper, put in your own, done.

If your replacement horn draws more than 10A, you will first blow the 10A horn fuse. The horn will not run at "reduced power", it will draw more than 10A and quickly blow the fuse, exactly as designed!

Depending on how risk-averse you are, you could consider increasing the horn fuse rating beyond 10A. Maybe 15A. You would have to convince yourself that the stock relay, connectors, and wiring would be fine for 15A draw without overheating or melting. (If it was me, I'd check all the wire gauges and connectors and see if there are other applications in the car that already use them for >10A.)

Note that there is no risk to your Horn Button in the wheel -- it doesn't carry the current. The horn button just switches the stock relay.

So, if you want to run a 20A horn off your 10A fuse circuit, your best bet is to use the existing power to switch.. another relay. A beefy one with bigger wires, and a bigger fuse going straight to the battery. That's the safe & sane thing to do, and it's really not that much extra hassle. Just another relay and wire run to the 12v battery. Then you can run 50A air horns, semaphore flags, and a strobe light.

A big thank-you, to all who have chimed in...

Is the OEM relay a standard 5 pin "bosch" type? Can I remove and replace the original relay with a beefier 20A, and the fuse with a 20A and keep the same wiring?

ELECTRIC - Bragging Rights!

 

[Deleted member 776]

I wonder if any of the other horn people replaced so far runs only on 10A? It seems like only the Stebel horn has mention of its own relay in this thread. Can others who had installed non-Stebel horns comment on how much current draw their horn is? And whether they come with their own relay or whether people were able to just switch out the old one and use the factory relay?

I would assume that the reason the factory horn sounds dinky and tiny in the first place is because it doesn't have enough power to make it loud enough. But maybe I'm wrong and there are other horns designed for only 10A draw that can sound much louder than the stock horn.

I bought the FIAMM EL GRANDE TWIN from Amazon, but have not installed it because I was not sure what its current draw was. The horn does come with a 30A relay, but after some looking I found a reference on the FIAMM website:

• 
  
  http://www.fiamm.com/linea.php?s=561&type=LINE&Prod=997
  

They mention a current draw of 10 Amps. So it appears to be OK with the existing relay.

 

[TonyWilliams]

Is the OEM relay a standard 5 pin "bosch" type? Can I remove and replace the original relay with a beefier 20A, and the fuse with a 20A and keep the same wiring?

Gosh, you really don't want to have problems, right? Would it work? Probably. Is it smart? I don't think so.

The wires going to the horn just aren't that robust. I didn't measure the gauge, but let's just say, it's not adequate for the load of a Stebel Nautilus Air Horn.

I guess I don't understand the aversion to just adding the proper gauge wire and fuse. I've spent more time typing this than running that wire (ok, not quite, but you understand ;-)

Maybe tomorrow I'll do a video of the install, done "properly". Do you think that might help?

 

[Volusiano]

I bought the FIAMM EL GRANDE TWIN from Amazon, but have not installed it because I was not sure what its current draw was. The horn does come with a 30A relay, but after some looking I found a reference on the FIAMM website:

• 
  
  http://www.fiamm.com/linea.php?s=561&type=LINE&Prod=997
  

They mention a current draw of 10 Amps. So it appears to be OK with the existing relay.

I think in this case, it's probably better to buy the FIAMM EL GRANDE TWIN for $16.57 than to buy the Stebel Nautilus Compact Air Horn then (at $27.49). Not only is it cheaper, you can just swap the new one in and use the factory relay already built in, and don't even have to come up with any extra wiring for it. The wiring kit designed for the Stebel can run you another $20 on top.

The only advantage the Stebel has is that it's just a little bit louder (139db at 4" compared to 130db at 4" on the FIAM EL GRANDE TWIN), and that it's a little more compact (designed for motorcycle in the first place). But compactness is not an issue at all in the case of the Leaf.

If I had to do it all over, I would have chosen the FIAM EL GRANDE TWIN over the Stebel Nautilus Compact for the reasons stated above. However, I may up the 10A fuse with something a little bit bigger, like a 15A because the FIAMM can blow the 10A fuse if it actually draws the full 10A as specified.

 

[hatuey]

Is the OEM relay a standard 5 pin "bosch" type? Can I remove and replace the original relay with a beefier 20A, and the fuse with a 20A and keep the same wiring?

Gosh, you really don't want to have problems, right? Would it work? Probably. Is it smart? I don't think so.

The wires going to the horn just aren't that robust. I didn't measure the gauge, but let's just say, it's not adequate for the load of a Stebel Nautilus Air Horn.

I guess I don't understand the aversion to just adding the proper gauge wire and fuse. I've spent more time typing this than running that wire (ok, not quite, but you understand ;-)

Maybe tomorrow I'll do a video of the install, done "properly". Do you think that might help?

I'm not opposed to running wiring, just thought it might be a neater install, if the OEM wires are the proper gauge - use the existing fuse holder and relay plug. Neat and clean, no extra untidy wires.

I looked at the horn relay and it is rated at 15amps. Couldn't see the wires - it's dark in my garage. I tried to remove the relay but couldn't figure out how. I didn't want to pull too hard. I might need to push the side in or something - i'll try again in the morning.

I'm trying to get everything figured out before my horn gets here.

ELECTRIC - Bragging Rights!

 

[OrientExpress]

I wonder if any of the other horn people replaced so far runs only on 10A? It seems like only the Stebel horn has mention of its own relay in this thread. Can others who had installed non-Stebel horns comment on how much current draw their horn is? And whether they come with their own relay or whether people were able to just switch out the old one and use the factory relay?

I would assume that the reason the factory horn sounds dinky and tiny in the first place is because it doesn't have enough power to make it loud enough. But maybe I'm wrong and there are other horns designed for only 10A draw that can sound much louder than the stock horn.

I bought the FIAMM EL GRANDE TWIN from Amazon, but have not installed it because I was not sure what its current draw was. The horn does come with a 30A relay, but after some looking I found a reference on the FIAMM website:

• 
  
  http://www.fiamm.com/linea.php?s=561&type=LINE&Prod=997
  

They mention a current draw of 10 Amps. So it appears to be OK with the existing relay.

The Fiamm El Grande Twin horn is a PnP (Plug and Play) horn so rewiring or adding an extra relay circuit is not necessary.

 

[Coffee_Slurry]

Another bonus to adding your own relay and battery wire: You can KEEP the stock horn right where it is.
Why not?
A mechanical buzzer horn makes a great pairing with the air-motor Nautilus type horns.

 

[TonyWilliams]

Another bonus to adding your own relay and battery wire: You can KEEP the stock horn right where it is.
Why not?
A mechanical buzzer horn makes a great pairing with the air-motor Nautilus type horns.

I think somebody already did this. If you hit the steering wheel horn button quickly, it will just toot the "sad" horn, and if you hold the button slightly longer than a nano-second, it will spin up the air horn motor for a real horn noise.

 

[derkraut]

I wonder if any of the other horn people replaced so far runs only on 10A? It seems like only the Stebel horn has mention of its own relay in this thread. Can others who had installed non-Stebel horns comment on how much current draw their horn is? And whether they come with their own relay or whether people were able to just switch out the old one and use the factory relay?

I would assume that the reason the factory horn sounds dinky and tiny in the first place is because it doesn't have enough power to make it loud enough. But maybe I'm wrong and there are other horns designed for only 10A draw that can sound much louder than the stock horn.

I bought the FIAMM EL GRANDE TWIN from Amazon, but have not installed it because I was not sure what its current draw was. The horn does come with a 30A relay, but after some looking I found a reference on the FIAMM website:

• 
  
  http://www.fiamm.com/linea.php?s=561&type=LINE&Prod=997
  

They mention a current draw of 10 Amps. So it appears to be OK with the existing relay.

The Fiamm El Grande Twin horn is a PnP (Plug and Play) horn so rewiring or adding an extra relay circuit is not necessary.

+1----I installed the Fiamm El Grande Twin Horns with no problems whatsoever. No re-wiring, no changing relay. It works like a charm. I did make myself a stronger steel mounting bracket, to give the horn assembly more stability.

 

[mbutter]

Upgrading my horn is now on my 'to do' list. I honked at a rather 'annoying van' (I'm being very polite here...) who decided it was perfectly acceptable to park in front of a store and block traffic while he ran in. My wife burst out laughing when she heard our 'whimper horn'. :roll:

Of course, that is not enough from stealing the Leaf every chance she gets.

 

[aqn]

If you use one of the Nautilus horns, [...]

The upshot is that it doesn't come on right away. On my motorcycle, a quick "toot" activates just the stock whimpy motorcycle horn.. enough for "Hi There, or 'scuse me."

If I hold the horn for more than a brief tap, the Nautilus spins up and asserts itself in a more assertive/vulgar way.

So, built-in delay by having a combination of mechanical buzzer and air horn. [...]

In GroundLoop's case, and in every aftermarket air horn installation that I have seen, there is a small delay between hitting the horn button and the horn sounding. I suppose it takes a fraction of a second to (re-)pressurize the air feeding the horn, either in the horn's air reservoir, and/or in its air hoses.

Personally, I prefer that when I hit the horn, that it sounds right now; even a delay of a fraction of a second seems an eternity. Because of that, I've always only used piezo-electric aftermarket horns, specifically Fiamms.

I think in this case, it's probably better to buy the FIAMM EL GRANDE TWIN for $16.57 than to buy the Stebel Nautilus Compact Air Horn [...]

The only advantage the Stebel has is that it's just a little bit louder (139db at 4" compared to 130db at 4" on the FIAM EL GRANDE TWIN), [...]

I would like to point out that with sound level, the scale is logarithmic: sound intensity doubles with every three dB. The Nautilus is a whole lot louder than the Fiamms.

That said, Fiamms are a huge step up from the stock horn, and are plenty loud for me.

 

[AmarilloLeaf]

Thanks are due to the original posters in this thread, for including such excellent, easy to follow instructions and photos.

I just completed my horn upgrade (the Flamm from Amazon). The whole process was easy. I decided to approach from the top.

I was expecting this to be hard, but pulling off those plastic fasteners on over the radiator was easy. I was impressed that the metal piece holding the original horn onto the frame was so soft and easily bent, too.

I lost an ounce or two of the coolant. What is that stuff ?!? My level is still above min, but if I want to add more, where do I buy more?

 

[gasmiser1]

All what Groundloop said is right. It's simple if you understand the requirements.



I looked up the Fiam 74100 El Grande Twin Horns that seem to be popular on this thread for its low price of $16.57 on Amazon, and I notice that it also comes with its own relay. It's not clear on its spec what kind of current it draws, however.

----------------------------------------------------------
I haven't had any issues with my installation of the El Grande Twin Horns and didn't have to use another horn relay. It's a very simple install if you follow the picture thread from OrientExpress and a HIGHLY welcome upgrade from the stock horn. Night and Day