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Tutorial: Replacing the factory horn

120K views 165 replies 97 participants last post by  ndrios12 
#1 · (Edited)
Yesterday a friend and I decided the stock horn on the smart fortwo just wouldn't cut it! In a traffic situation where I would need to use the horn to alert another driver of my presence I feared the stock horn was not loud enough and could not project over general road noise and vehicle music of other drivers.

So without even tearing into the smart to find the stock horn I decided to purchase a Compact Italian air horn to replace the factory horn.

I bought this product from Griot's Garage. The horn retails for $39.99.

From here it was time to get in the smart and locate the horn. As I assumed the horn is located under the front bonnet on the driver's side of the vehicle. It can be seen by locating the power and ground wire that connect and the small bracket that holds it on, but with out removing the body panels there is no way to clear get to it.

So we started removing the body panels. First the front bonnet, next the driver's side side-skirt, then the driver's side wheel arch, and last a few front clips. The trick we learned here is that the body is very pliable and only required loosening from the body and did not need to be entirely removed. From here we had a clean look at the factory Bosch horn.





After removing the two wires from the back of the stock horn, we next removed the bracket from the body of the vehicle. The bolt was secured but only required a basic ratchet wrench.

Once, the stock horn was off, we plugged in the new horn to test for power, and to verify the product was functional. It worked perfectly!

Next we had to see how we would mount the new horn. The important thing here is to make sure the air horn was facing in a good direction so after a few test ideas, we were able to fit it in perfectly while using the stock brackets. Not a single bit of bending or cutting required! As you will note in the next picture rather then bolting from the front side of the bracket we bolted from the backside where there was more room for the new horn.



After we plugged the new horn in and tested it once again, we began to button up the body panels. Once everything was backed together, I took the vehicle for a quick test drive down some empty roads and just gave the horn some freedom.

Results: The horn is very loud and will get the attention of everyone around you. It kinda makes you laugh when you here it but more importantly it gets the attention of the driver who's blind spot you are in and begins to switch lanes in to you! For anyone who has spent time commuting on motorcycles, you understand the safety that a horn loud enough to be heard can bring you and I feel this is a great modification for the smart fortwo.

 
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#35 ·
I couldn't figure out all the attachment points for the panels so I had to get as much loose as I could and squeeze the horn in place. Would like to eventually learn how each panel is removed.

Mine only worked with Brown connected to negative (-). I noticed the vent opening and chose to mount the new horn in front of the bracket in the same spot as the stock horn. With this position the horns flare forward just below the center grill.

Sounds good and loud.
 
#42 ·
Dave,

Do you have any other photos of your install?

Still not convinced completely with the effectiveness of the fanfare horn... I purchased both, the OEM Fanfare horn and the super loud air horn which I think would be more effective where i live (we have about 2 accidents a day where truckers smash cars when they merge carelessly.)

I want to put in the an air horn when the car arrives. The dealer won't touch the air horn because it is non-OEM. I have seen the suggestions for the install of the horn, but I don't want to break anything and fear I might get started and not have a tool I may need. I have never done anything like this before. The last horn I installed was accessable when you opened the hood, it took seconds to swap out. The smart appears it will be a challenge since the dealer refuses to help me. I wish there was a "how to" guide to remove the panels, you think they would provide one since they tout the removal of the panels in almost everything they market on the smart. It almost seems they intentionally want us to try and break something. Gerrr.... Any suggestions?

Does anyone plan on removing the panels, if you do I am sure we would all appreciate (maybe even pay for) a step by step "how to" with photos of the process. Where the screws and clips are to include any warnings along the way. Even a list of tools that will be needed / recommended... Any thoughts?
 
#47 · (Edited)
Here is a visual tutorial with a breakdown of steps

OK here is a real writeup. Don't get me wrong, the first walk through I thought this going to be cake. But the directions left a lot of detail which hurts when you do not know what the heck you are doing.

I'll be honest it took me a good 3 hours of breaking down everything to get the factory horn swapped out with this Stebel Nautilus horn. The horn is available everywhere. You can go to http://www.google.com/products?q=stebel+nautilus and you will find it for about $33-$45, with tax/shipping estimate about $50.

Ok here is the detailed walk through:

Here are the tools you'll need:
25 Torx wrench
Adjustable Wrench/socket wrench
Needle Nose Pliers
Flathead Screw Driver

Time: 3+ Hours depending on how good you are with a car (It took me
longer because it was the first time disassembling my car, now I can do it in 20 minutes)

Difficulty: Medium

1) Remove the hood, Below is a yellow circle of the hood screw. Also remove the hood skirt screws labeled with the red circle.

2)
2) With the hood out of the way you will need to remove the bonnet screws on the drivers side. The yellow circle is the bolt you need to remove



3) Next open the drivers side door. You will need to remove the retaining pin with a screw driver or your fingernails and then pull it out or use the pliers. Next you will need
to remove the torx retaining pin that holds in the antenna cover. Take a screwdriver and put pressure on the base and then you can unscrew the torx retaining pin.

The car door retaining pin




3) Next you will need to remove the drivers side skirting. This is a tricky part and has the most potential for damage. For those of you that aren't familiar with removing carpanelling, there are screws that face the outside. The retaining clips are attached to the door. When you pull the panel off there is a pressure on the clips. Because they are plastic and they have an easy potential for breaking so you will need to use caution in taking the side skirt off. First go to the back wheel on the drivers side. You will see two retaining pins. Remove those first, The first picture is a close up of those, again the circles in yellow indicate the retaining pins.



4) With the retain pins out you will need to pull the end of the panel (towards the rear wheel) out slightly so that the snap tabs on the end of the panel come out. With the rear of the side skirt removed, you will need to push the side skirt slowly forward to remove it. Another way to do this is to slowly pull out the panel by gently apply pressure. If you apply too much pressure, the the side skirt clips will break of or chip off depending on how hard you pull. On the bottom of the panel (which is under the car) there are snap tabs there also, but they will come off as you get the skirt removed from the car. As you can see here the retaining clips are circled in yellow. I broke off parts of two of mine. You can see the red circles are the pieces of the clips, which is what happens when you apply too much pressure.



5) Next step is to remove the remaining bolts from the front side panel. Before you can do this you will need to remove the antenna. Simply unscrew the antennae, The antenna cover should be ready to remove. If you forgot to do step 3, you can remove the torx retaining pin now. To remove the cover Using a blunt screwdriver that you can place under the cover and slightly lift. You will reveal another retaining pin and a torx screw. Unscrew the torx screw and pin and the panel will ALMOST be ready to removed.



6) Once you do the top part of the front driver's side panel, the bottom needs to have its final screw removed. Take a look at the yellow circle, this is where the final torx screw is located. Once it is remove the driver's side front panel can be space out from the car while still attached to the rest of the car. The original walk through mentions that the panels are very pliable, however be careful here if you spread/bend them to far there will be some warping. Mine did not warp but I can tell from the pressure against the plastic that it will warp and cause warping of the paint.



7) Now that panel is removed you can see the entire driver's side front area. You will see the radiator along with horn. Below is a picture of the stock horn removed. Simply remove the two wires that are attached to the stock horn. Next reach in through the top of the front and use your adjustable wrench to unbolt it from the chassis bar. Once it is remove you can take it out and prepare the the air horn for installation. The stock bolting works but you will need to bend the mounting bar into towards the driver in order to secure it. The original walkthrough says you don't need to bend the chassis bar, butin order to firmly bolt the horn in I bent the chassis bar towards the driver. Also if you look at the original picture of the horn. The silver part of the horn must stay within 15 degrees from a straight line at zero (This is per the main instructions from Stebel's site). If you look at my picture the blue line is 0 degrees and the orange lines are ABOUT 15 degrees each way. Mounting the horn is a little tricky. First stick the head of the bolt through the chassis bar so that the long end is facing the driver. Screw on the bolt that came with the air horn so that they are connected. The retaining mount on the horn will slip into this and then you can tighten up the bolt. I found as I tightened the bolt I need to bend the chassis bar a litte bit more towards the driver until it was snug. Trust me you dont wan't the horn coming off while driving on some potholed roads (like here in Los Angeles). Finally plug in the two wires into the horn. The brown is the negative (this is common for european cars) the blue is positive. If you happen to reverse them, when pressing on the horn you will getting a whirring noise. Just swap them and turn on the car and test.


Old Horn


New Horn

8) Now that the horn is installed you must reassemble the car. First put the drivers side front panel on in reverse way we took it off. Put the two main torx screws back on. (Step 5 and Step 6) Don't forget to put in the retaining pins.Next snap back on the badged antennae cover and screw the torx retaining pin back in. Also check that the points are all lined up on the car. Each of the tabs/retaining holes should line up pretty close.

9) The drivers side skirt was the most difficult part to back on. A) because I chipped some of the tabs on them, B) It took me a while to figure this out. First unscrew all the white retaining clips that are on the screws. The screws will stay in the car. Next if you look at the inside of the side skirt you can see 5 insertion points for the retaining clips. Slide all the retaining clips into these points. Look for the original mark of where the retaining clips went. You will see pressure marks on them. Next you will need to insert the front end of the skirt into the driver's side panel. Next make sure that those bottom side clips on the skirt are sitting above the bottom car panel. You can barely see this, but you will need make sure this is done, otherwise part of the skirt will be hanging out underneath the car. Finally line up the white retaining clips with the screws. Push the panel in making sure the clip tabs at the end of the panel (towards the rear wheel) snap in. Also make sure the skirt is in front of the front wheel well panel. Sorry I don't have pictures of this because I was getting frustrated with the side skirt. The skirt should sit flushed with the car.

10) Replace all the remaining hood screws and retaining pins. Screw back on the antenna. Finally reaattach the hood and verify that all your panel seems are close to what they started at. If they are too spread apart the hood will not look like its attached correctly. If it is you should be good to go. If you honk your horn you will get the nice loud tone. I did notice that the lights dim a little when the horn goes off.

I suggest washing you're smart car when you are done because I guarantee there will be fingerprints everywhere along with grease and dirt stains from the work. Also when you start removing panels dust kicks up.

Happy Driving and good luck. I love my new horn it got the neighbors attention twice this morning.
 
#48 ·
OK here is a real writeup. Don't get me wrong, the first walk through I thought this going to be cake. But the directions left a lot of detail which hurts when you do not know what the heck you are doing.
...
Awesome, thanks :)

Looks like the same horn Aerostich is selling http://www.aerostich.com/product.php?productid=19550&utm_source=sl2008_4_10&utm_medium=email (and they told me it works well in cars too; I like the company, good people with good products).

Let us know how you like it on the road :D
 
#54 ·
Sorry in the midst of reinstalling the horn I was in a hurry to get my car back up and running. I might remove the hood pieces tomorrow or sometime this weekend.If not I can always take a picture of from the grill. It is pretty flushed so it might be hard to even make out... I'll update this tomorrow morning.
 
#55 ·
HOLY JUMPIN' Jahassifers!!! Man you really like to do things the hard way!
Here is a simple text explanation of how to do this simple job......

Break left front wheel lugs loose but don't remove....
Jack car on left front jacking pad high enough to install safety jack stand.
Remove wheel.
Remove 3 plastic expansion retainers from left front splash shield...fold back front part of splash shield to gain access to horn mount bolt right there in your face...unplug the two wires to the horn, remove the bolt and then the horn out thru opening. Install original mounting bar onto new horn and bolt right back into same place.
Hook up wires...Brown is NEGATIVE, Blue is POSITIVE.
Push back splash shield and reinstall expansion retainers. JOB DONE

Total time including all the periferal stuff....about 20 min to 1/2 hour....:D

Just thought you would like to know you don't have to take the whole front of the car apart to do this job!

John
 
#58 ·
Oh now you tell me!




I started installing my Stebel Nautilus mini airhorn yesterday at 8:20 am, minutes before you posted. Argh!!! Just kidding, that's a great suggestion, John. It took me about 1.5 hours, mostly due to removal and refitting of the side skirts, which was a major pain. In the end, I realized you don't have to slide the skirt back onto the white plastic clips for the reinstallation; you can line up the holes in the skirt with the clips and gently push the skirt on. It simply clicks on (or at least it did for me).

Anyway, the horn sounds great.

Floyd
Sacramento, CA
 
#57 ·
Me too, Tom...

I knew if I waited long enough someone would find the easy road. FYI I used bracket to mount scangauge same place as yours I like it their. I will mount horn this afternoon.

Regards, Tom
I kicked around all the other suggestions and methods and came up with what I did. Other than one other place, which would have been so cool but a much harder install, I elected to put it there.
That other place is just immediately above the "passenger side air bag off" light and there is room there for it. Removing that panel plus fishing the wire down the side windshield trim and then back across to the OBDII plug- in would have required me to make up another extension wire to give me enough length to reach the OBDII plug. I opted for the low road and not to cut a hole in the upper windshield interior valance....:( It would have looked like a factory install there, though....:)
 
#59 ·
John your the Man!!!!

John, Came home fron church changed and had new mini horn in 27 min. start to finish. TA DA!!!!! Thanks again for the post my next part will be the new muffler from Doug's Headers have placed my order little sports car purr is ok not into fart can sounds well past those days. I had Doug headers back in the 60's when you could still build a motor on saturday and blow it up sunday at the drag strip the good old day's 5 mpg 25 cents a gal.


Stay safe Tom
 
#60 ·
Doug Thorley Muffler...

John, Came home fron church changed and had new mini horn in 27 min. start to finish. TA DA!!!!! Thanks again for the post my next part will be the new muffler from Doug's Headers have placed my order little sports car purr is ok not into fart can sounds well past those days. I had Doug headers back in the 60's when you could still build a motor on saturday and blow it up sunday at the drag strip the good old day's 5 mpg 25 cents a gal.


Stay safe Tom
I may get one of those to r&r the original when it burns out..if I have the car that long. This one will be traded for a Smart PHEV or EV when they come out.
 
#61 ·
I just installed the Stebel, this afternoon. After removing the front left wheel, I pulled off one fastener at the front of the wheel well and bent over the plastic inner fender to find the original horn and bracket. The Stebel went in with a little finesse. The Stebel is slightly lower in tone than true Italian air horns but just as loud and attention grabbing.
 
#62 ·
Stebel Nautilus airhorn

Hi gang, I put two of the Nautilus airhorns in a couple of years ago on my 450. I added a relay and a switch so that I can go from the stock horn to the airhorns (and the stock horn) when I wish.

Here is a clip of the stock horn vs the end of the world horn. Two stebels test at nearly 140 dB at 6'. If you watch closely, you'll see that I jump when my wife lays on the airhorns the first time. lol.

They have seen a lot of use and they are still 100%.
 
#63 ·
I also put one of the Stebel Horns in this weekend by going through the wheelwell removing the one wheelwell fastener and it was a piece of cake. The hardest part of the install was removing the wheel. I did install the supplied relay using the existing Hot and ground wires. Just jumpered the Hot constant with the horn button Hot and horn supplied Grnd to the relay grnd and horn grnd. Worked perfectly! Sounds MUCH better than stock!:)
 
#65 ·
No, I don't think so....



It is not necessarily the height needed but the room to get your body into the wheel well in order to be able to reach in far enough to get where you need to. I thought maybe turning the wheel to the far left would help but there just wasn't enough room. You need to get both hands in there..one to hold and one to wrench....I am broad shouldered so I needed all the room available by removing the wheel.
 
#66 ·
Can someone please get some photos of this process and where the fender fastener is? This process sounds much easier than trying to take off the entire side panel...
Photos with some basic direction would be amazing and very useful and swaping the horn in the US seems to be VERY popular...
 
#67 ·
There are three plastic " nail- wedge " fastners which hold the front and outside of the fender liner in place. They are removed by pulling the "nail" which is the pin in the center of the fitting. I used a plain old claw hammer to do this easily.

Be careful not to over bend the fender liner or it will get a crease in it I'm thinkin....

I installed the Stebel horn a couple days ago and it works fine. It is a TIGHT fit but it does indeed fit.
 
#68 ·
Results: The horn is very loud and will get the attention of everyone around you. It kinda makes you laugh when you here it but more importantly it gets the attention of the driver who's blind spot you are in and begins to switch lanes in to you! For anyone who has spent time commuting on motorcycles, you understand the safety that a horn loud enough to be heard can bring you and I feel this is a great modification for the smart fortwo.

[/quote]

I think it would be really great if we could get together somewhere and have a "mass" horn exchange meeting. Perhaps those that have already done theirs could meet up with all of us "newbies" who are too scared to try removing body panels and doing the work on their own. It would be a great excuse to get a bunch of smarts together, and it sounds like it's pretty obvious that the horn on the smart fortwo is totally inadequate. If it's anything like the one on my Chevy Aveo, NO ONE is going to hear it when you NEED IT!!!
 
#69 ·
It is a bit goofy that I bought a motorcycle horn, the Stebel, to put on the CAR and in turn installed the Smart CAR horn on my poor bedraggled old motorcycle immediately. My nasty old harn hadn't worked on the sidecar rig in a couple years... so re-using the Smart horn seemed the " rational " thing to do at the time. It will live on thanks to the Smart transplant team.....

:)
 
#70 · (Edited)
I just installed the same horn (purchased at aerostich) via the wheelwell. Things are a bit cramped and scrapy on the hands but easy enough to do and much easier than removing all the panels.

I diverted a bit from all the previous installs by removing the stock horn from the bolt holding it to the bracket and used a hardware store bracket to bridge the stock bracket to the horn mounting point so it could be mounted with the horns facing forward, not backwards as the pictures in the original install shows. With the added bracket the new horn can be mounted with the assembly perfectly vertical and in the same forward position as the stocker.

It's loud as heck and I love the dual-tone, well worth the price of admission!
 
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