2018 LEAF Horn Upgrade DIY

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OrientExpress

Well-known member
Joined
Aug 8, 2010
Messages
1,651
Location
San Jose, Ca
The horn from the first-generation LEAF carries over to the second-generation car, and the desire to upgrade it is just as strong.

For the ’18 car the position of the horn has changed from being in front of the radiator to down on the front lower right side of the body bulkhead. The area where the horn is now is very tight, and access to the stock horn bracket is just about impossible without removing the front bumper cover.

The horn is still powered by a “floating ground” circuit with a positive and negative connector. Because of the horn’s tight location, adding dual-tone horns requires that they be mounted elsewhere in the engine compartment and a longer pigtail connector be fabricated. The new location will also require a longer custom mounting bracket than before.

Most of the task of installing the new horn is accessible from the top of the motor compartment but accessing the stock horn and its wiring harness is somewhat of a pain.

For my 2018 LEAF SL, I moved the Hella Super-Tone horns that I originally had in my 2014 LEAF SV to the new car.

18LEAFHorn-00.jpg

My Hella SuperTone horns in my '14 LEAF

This is how I did it, and where I placed the new horns. No special tools were required.

Suggested tools:
-car floor jack
-jack stand to support the vehicle
-Phillips screwdriver
-13mm and 10mm socket
-some zip ties
-some 18-gauge wire and spade connectors
-a piece of mild steel or zinc strap mounting (also called mending plates) to fasten the horns to the car
-a drill to make holes in the mounting bracket
-a tack puller to remove the push fasteners

If you are moderately handy, this DIY should take you about 90 minutes. If this whole thing gives you the sweats, this may not be for you. As usual, I take no responsibility for your success or failure with this DIY.

Getting at the stock horn and its connectors
Because of where the horn is located on the ’18 LEAF, this task is the most involved. It’s not necessarily hard, it’s just requires removing the right-side wheel well liner to reach up in the nose to unplug the horn cable.

Removing the wheel well liner.
1. Jack up the right front wheel, place a floor jack stand next to the jack for safety, and remove the wheel.

18LEAFHorn-01.jpg

Remove the mud flap first and move forward

2. Next remove the mud flap at the back side of the wheel well. It is held in with a couple of Philips screws, push-fasteners, and some foam tape. Set that piece and its fasteners aside.
3. Remove the wheel well liner. It is held in with a bunch of push-fasteners that are easy to remove. I use a tack puller to reach under the push tab to pull it out. The tab comes out partway and then the entire fastener is removed by hand.

18LEAFHorn-02.jpg

Gently pry out push-fastener center and then pull it out by hand

4. After all the push-fasteners are removed, then the front of the liner under the bumper cover has eight screws and 10mm bolts that need to be removed. Pro-Shortcut: If you have small hands, just removing these screws and bolts and a few of the leading edge of the wheel well liner fasteners can give you access to the horn.

18LEAFHorn-03.jpg


5. Gently pull the wheel well liner out and set it aside. You now have good access to the horn.

18LEAFHorn-04.jpg


Unplugging the horn cable.
1. Reach up in front of the windshield washer tank and feel for the horn.

18LEAFHorn-05.jpg


18LEAFHorn-06.jpg


2. There are two wires attached to the horn, gently wiggle each one back and forth until they unplug. They have a bit of length to them so pull them down so you can see which one is positive and negative. The positive one has a brown connector and negative is black. Because of how the stock horn is mounted, I recommend just leaving it in place.

18LEAFHorn-07.jpg


Mounting the new horns in the motor bay
1. Remove the front top motor bay cover. It is held in with 10 push-fasteners like the wheel well liner. Take care not to drop any down in the motor bay. If you do, you may have to remove the motor bay belly pan to get them out. I found that the area with the most space for mounting the new horns is on the left side of the motor bay adjacent to the radiator mounting frame.

18LEAFHorn-08.jpg


2. Make a new horn bracket. I took a piece of .018 zinc mending strip that I got in the hardware section of Home Depot, to make the horn mounting bracket. These strips are easy to bend, drill holes for mounting the horns, and mounting the bracket to the car. They are available in different lengths and shapes. I took one that was T-shaped and cut it into an L-shape for this mounting.

18LEAFHorn-15.jpg

Mounting strips come in a variety of lengths and are available at any hardware store

3. I found that the 13mm bolt holding the radiator mounting frame to the car on the left side was the best place to mount the horns. I bent the mounting bracket 90 degrees to place the horns on the side of the radiator in front of the 12V battery.

18LEAFHorn-10.jpg


4. After bending and drilling the mounting bracket to fit, bolt the horns on the mounting bracket and test fit it. Make sure that the electrical connectors on the horns face up so that they are less likely to get corroded. Make sure that the horn bracket does not wiggle after it is tightly mounted to the radiator frame. If it does, stick a piece of foam padding between the horn assemble and the radiator frame.

18LEAFHorn-11.jpg


5. Do a test fit of the plastic top motor bay cover to make sure that the horns do not interfere with its placement. Adjust your horns and bracket as needed.

18LEAFHorn-12.jpg


Wiring the new horns to the existing horn circuit.
1. IMPORTANT: Determine if your new horn’s electrical connectors have a floating ground or a chassis ground. If the horns have a chassis ground, then the connectors are polarized and it matters which connector the positive wire is connected to. If you plug in the hot wire to the ground lead, you will blow the horn fuse, and spend the rest of the day trying to figure out where that fuse is. If you have a floating ground horn, the electrical connections are not connected the body of the horn and it does not matter which connector the positive lead is connected to.
2. To determine if your horns have a floating ground or a chassis ground, take an ohm meter or continuity tester and connect one lead to the stud on the horn that is used to bolt it to the mounting bracket. Take the other lead and connect it to each of the horns electrical connectors. If after testing each connector for a connection to ground, if neither indicates a circuit to ground, then you have a floating ground. It does not matter which lead on the horn the power lead is connected. BUT if one lead on the horn does show a connection to ground, mark that lead as the negative lead, and the other as the positive lead. This will ensure that you won’t be looking for blown fuses later on in the install.
3. Make the horn extension pigtail that will go from the stock horns connectors to the hew horns. Cut two pieces of wire long enough to reach from where your new horns are going to be mounted to where the original horn connectors are in the right front corner of the car. I suggest making one out of red wire and the other black just to keep things straight. Use blade crimp connectors on each wire, female connectors on the new horn side and males on the original wiring side. I also recommend putting the two wires in plastic sleeving to keep them together. I routed the wires along the radiator mounting frame and over in front of the windshield washer tank down to where the old horn is at.

18LEAFHorn-11.jpg


4. For each wire, make a series connection to the horns with two spade connectors, one for each horn. The red wire goes to the positive connection on each horn (does not matter if the horn has a floating ground), and the black wire goes to the other connector on the horn.
5. Zip-tie the new horn wiring harness as needed to the car, and make sure that the connectors on the horns are insulated so that the power lead can’t get accidentally grounded and blow the fuse. I use shrink tubing to make sure the connectors are properly insulated.
6. Next connect the other end of the pigtail to the original horn connectors that are down where the old horn is. If your horns have a chassis ground, before you connect the power lead, check one more time that you have the power lead on the new horns connected correctly.
7. Once the new horns are connected, push the horn button on the steering wheel VERY briefly. If you get a toot, congratulations you did it! If you get silence, check your connections again.

Putting your LEAF back together

18LEAFHorn-09.jpg


This is the easy part, and the goal here is not to have any parts left over, or not enough parts to get everything bolted or fastened back together.

1. Make sure that the physical connections of the horn electrical connectors are solid. Make sure that the 13mm radiator frame mounting bolt that the horn bracket is mounted to is tight secure and level.
2. Replace the front top motor bay cover and it’s 10 push connectors.
3. Make sure that the new horn wiring harness is secure, up out of the way and that the connections are tight. I put a piece of shrink tubing on those connectors to make sure they stay dry.

18LEAFHorn-13.jpg


18LEAFHorn-14.jpg


4. Reinstall the wheel well liner. I start with the push connectors inside the wheel well and work around to the front of the liner, with the screws and bolts, then the last thing to reinstall is the mud flap.
5. Bolt the wheel back on, the proper torque for the lug nuts is 83 ft-lbs.
6. Pull out the jack stand, and lower your LEAF
7. Get behind a big-ass SUV and test out your LEAF’s new voice!
 
beautiful pictures, thank you for making the time to document this on your new car for everyone. this post will have long life.. I might get a 2018 leaf in about 2021 or 2022.
 
Thanks for the great write up! I just got my leaf and heard the need for a new horn right away so I'm looking forward to installing some new horns later in the summer. I really appreciate the clear photos and instructions.
 
Thank you so much for that very clear and comprehensive write up. I just spent half an hour with my head under the hood trying to figure out how to do this (my new horns should be here by the weekend) and your write up confirms and clarifys pretty much what I was thinking.

One thing I will do differently is change the sequence. I will mount the new horns and run the wire to the stock horn before getting the wheel well and liner off; I would hate to disconnect the stock horn and then find I couldn't get the new ones mounted for some reason!!
 
Upgrade done and I am very happy. One major departure from your post, I put the new horns in the left front wheel well because it is empty. I found a very handy frame joint with two bolts (I'd call them 1/2" but they are metric) one of which I used as a very solid mount for my home made bracket. The horns came with a 12V relay so I use very little power from the original circuit to activate the floating coil, however I have an ugly in-line 10A fuse between the battery and the horn power relay contact.

Thanks again for helping my car get a proper voice!!!
 
Hi all, this is my first post here. Just picked up my 2018 SL a month ago and I LOVE it! Except for the absurdly low horn. My mountain bike has an air horn that is tenfold louder than the Leaf’s! I already had multiple close callls in which I honked hard to avoid accidents and the othe drivers simply cannot hear my horn. It is very unsafe. I don’t understand how any automaker may be ok with this. I called Nissan, spoke to a condescending customer “service” rep, and not only was she of no help, I was told that dealers are not allowed to replace any stock part from the Leaf, including the horn, and, if I replace it myself, I’ll be voiding the warranty. THAT worries me and pisses me off! Even if the voiding of the warranty is for any possible related issue (electrical malfunction), they can use that as an excuse to not honor the warranty. Has anyone had such issue with Nissan? You guys that went ahead with replacing the horn, what’s your take?

I feel perhaps what’s needed is a class action lawsuit for the unsafe horn, which is a safety device, and then that would pressure them to do a recall and install a decent horn, instead of this garbage.

Cheers!
 
BlueMapleLeaf said:
Hi all, this is my first post here. Just picked up my 2018 SL a month ago and I LOVE it! Except for the absurdly low horn. My mountain bike has an air horn that is tenfold louder than the Leaf’s! I already had multiple close callls in which I honked hard to avoid accidents and the othe drivers simply cannot hear my horn. It is very unsafe. I don’t understand how any automaker may be ok with this. I called Nissan, spoke to a condescending customer “service” rep, and not only was she of no help, I was told that dealers are not allowed to replace any stock part from the Leaf, including the horn, and, if I replace it myself, I’ll be voiding the warranty. THAT worries me and pisses me off! Even if the voiding of the warranty is for any possible related issue (electrical malfunction), they can use that as an excuse to not honor the warranty. Has anyone had such issue with Nissan? You guys that went ahead with replacing the horn, what’s your take?

I feel perhaps what’s needed is a class action lawsuit for the unsafe horn, which is a safety device, and then that would pressure them to do a recall and install a decent horn, instead of this garbage.

Cheers!

You may want to do some research on the https://en.wikipedia.org/wiki/Magnuson–Moss_Warranty_Act

The rep you spoke with is very ignorant regarding American automotive aftermarket parts modifications & new vehicle warranty if you're located in the US. If not then I have no idea what protections you may have.
 
I wrote the original horn upgrade DIY in 2011, and can assure you that there are no restrictions on how you modify your LEAF, especially when upgrading the horn.

A little background on horns on Japanese vehicles. There are two types of horns that are approved in Japan, a “city” horn, and a “country” horn. The differences are in the horns tone and how loud it is. There is also a dual-tone horn that is an available option.

For Nissan their product planners have settled on the city horn for all their cars. I’ve advocated directly to Nissan US Product Marketing to change the horn for years, but have yet to be successful.

As you can see from my DIY for the ‘18 LEAF, the placement of the stock horn is a little bit difficult to get at, but upgrading the any of the dual-tone horns out there is something that just about anyone can do.
 
Thanks for your responses. I’m in Canada, so not sure if laws differ vs the US. What I can tell you, though, is that the Nissan rep pointed me to the exact spot in the warranty booklet which states that any modification will void the warranty. That’s Nissan covering their ass. So for them it’s a matter of black or white. No shades of grey. Replacing the horn is a mod, hence you’ re risking your warranty if anything fails which they could claim was caused or affected by it. Very frustrating!

Over the weekend I hoisted the car with a jack, removed the front right wheel, and loosened the liner, as per the tutorial in this thread (truly appreciated!!!). I concluded that to either replace the horn or add it in parallel, I’d really need to hoist the car fully and remove the liner completely, maybe even the bumper. Not something I can do on my back on my driveway. I may end up going to my mechanic. Just need to decide whether to replace the horn with a Hella 2-tone one (which I already got at Amazon) in an inconspicuous way, or, add it to the stock one in which case it would be very visible from the top when you open the hood. And hope for the best....
 
No you don't need to remove the entire belly pan, just the right front wheel liner. Of course you could remove the entire front bumper cover, but that is more work than necessary.
 
Cool, thanks! I decided to take upon myself to do it this long Canadian Thanksgiving weekend. I found a perfect spot for the 2-tone horns, facing front, attached to the top crossbar, using a T bracket and each horn's tab, forming a sideways " H ". I will post some photos. An image is worth a thousand words!

I'm planning to add the horns to the stock one, by splitting the wires as follows (blue wires are the Nissan original which I then split 3-way, represented by the orange wiring, to connect all 3 horns):

uc


Does that make sense? By the way, the Hella horns have no markings of positive or negative connectors, so I'm guessing it doesn't matter which polarity I connect in each connector.

Also, what gauge wire can I use? I purchased 14 gauge but it seems too thick to do those 'Y' splitter connectors. Actually even a single piece of stripped 14g won't fit the terminals. Would 18 or 20 gauge be too thin a wire (in terms of amperage) or would it work ok? It's a short run between the horns, maybe 1m to 1.5m (3ft - 5ft).



Thanks!
 
Had some time this afternoon and I did it! It all came together nicely, but I must say that the stock horn connectors are in the worst possible location. It took me forever and scratches to both my arms to connect the new wiring to both its connectors, especially the positive one. But I was finally able to do it. The wiring was exactly what I drew in my previous post. Worked perfectly.

There is only one glitch I'm a bit puzzled. I was sure that the car-locked alarm confirmation came from a separate horn/speaker. Now, when I press the lock car button, I get a deeper tone, much shorter and softer than before. I tracked where the sound was coming from and all 3 horns are creating that confirmation sound. My guess is that given it must be a shorter burst of power to make that sound, it now has to be split into 3 horns, hence creating a lower-powered sound. Otherwise, it is is a different horn, I don't see why it would be affected by my adding 2 horns. Any ideas?

Here are the photos of the final location of the horns, using the T bracket. The photos' perspective is from the engine looking towards the front. The only tricky part was threading the nuts onto the screws, inside the crossbar from the bottom, without dropping them into the engine compartment. My wife helped here with her tinier hands.

uc


uc


uc


uc


Cheers!
 
BlueMapleLeaf said:
Cool, thanks! I decided to take upon myself to do it this long Canadian Thanksgiving weekend. I found a perfect spot for the 2-tone horns, facing front, attached to the top crossbar, using a T bracket and each horn's tab, forming a sideways " H ". I will post some photos. An image is worth a thousand words!

I'm planning to add the horns to the stock one, by splitting the wires as follows (blue wires are the Nissan original which I then split 3-way, represented by the orange wiring, to connect all 3 horns):

One concern would be the current draw from running 3 horns in parallel. This is all on a 10A fuse, iirc. Since you already have it installed, I'd recommend a good long horn blast (maybe 5-6 seconds) just to make sure. If the fuse handles that you're probably ok.
 
Good point. But If it's indeed too much, I suppose the fuse will blow, and then what would be a solution? Replace the fuse with a 15A or 20A one?

Thanks!
 
BlueMapleLeaf said:
Good point. But If it's indeed too much, I suppose the fuse will blow, and then what would be a solution? Replace the fuse with a 15A or 20A one?

Thanks!

I would not increase the fuse size without making sure that wire size or electronic switching/power distribution modules are not limiting factors. We have experience with dual horns being OK on the 10-ampere circuit, but the OEM horn may add too much.
 
Honked for a period of 6-7 seconds and still working. Sounded solid and the fuse held up fine. My only beef is the awful sounding (very low, muffled and anemic) remote door lock beep/honk/ confirmation. Again, I suspect the locking process does not provide or trigger enough power for a proper honk of 3 horns. Plenty for a quick chirp of the crappy OEM horn, but not enough for an additional double horn. I haven't tried disconnecting the new ones and see what happens. It would be very easy and quick. I will do so when I have a chance. In any case, for safety, I'd much rather have a decent horn than a louder door lock confirmation!
 
Considering the stock horn is anemic to begin with, why don't you just pull the wire off on it, and use the 2 new horns? That way you don't have to worry about overloading the circuit..

You would still have a working circuit for the stock horn to reconnect if you sell the car?? Just protect the detached wire plug with electrical tape..
 
powersurge said:
Considering the stock horn is anemic to begin with, why don't you just pull the wire off on it, and use the 2 new horns? That way you don't have to worry about overloading the circuit.

That is what I recommend in this DIY. The stock horn is not in tune with the new horns anyway.

18LEAFHorn-13.jpg


One note: On my 2018 SL the door locking acknowledgement is a synthetic tone not a beep from the analog horn.
 
OrientExpress said:
powersurge said:
Considering the stock horn is anemic to begin with, why don't you just pull the wire off on it, and use the 2 new horns? That way you don't have to worry about overloading the circuit.

One note: On my 2018 SL the door locking acknowledgement is a synthetic tone not a beep from the analog horn.
If you try to lock the door with the remote control, it uses analog horn. The synthetic tone is only when u lock/unlock the door via the door handle.
 
BlueMapleLeaf said:
Honked for a period of 6-7 seconds and still working. Sounded solid and the fuse held up fine. My only beef is the awful sounding (very low, muffled and anemic) remote door lock beep/honk/ confirmation. Again, I suspect the locking process does not provide or trigger enough power for a proper honk of 3 horns. Plenty for a quick chirp of the crappy OEM horn, but not enough for an additional double horn. I haven't tried disconnecting the new ones and see what happens. It would be very easy and quick. I will do so when I have a chance. In any case, for safety, I'd much rather have a decent horn than a louder door lock confirmation!

I replaced the stock horn with Hella horn sharp horn over the past weekend.
Thanks OP for the nice well written guide. I did the same way OP did, unplug the stock horn and extended the wires (18AWG wire) to the same location OP points out for the new Hella horn. Except i did not take the entire wheel well out as i don't want to remove the mud guard.
As for your low door lock tone, i have the same behavior after i replaced with the Sharp tone Hella Horn. It didn't bother me much as i normally don't use remote control to lock/unlock the door.
 
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