How-To: Install Air Horns In Your 3rd Gen

tunersteve

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2011 Mustang GT
Recently I decided to upgrade my horn, instead of replacing it with a larger horn, I opted for a set of Fiamm Dual-Tone trumpet air horns, to kick it up a notch.

First off, If you screw your car up in any way, I am NOT responsible for this. This can/may void parts of your warranty in your car and I would just like to address this before you continue.

Total time to complete: 1-2 hours

Tools needed: 10mm socket, 10mm wrench hacksaw, adjustable wrench, drill, 5/16 drill bit, soldering iron(if necessary)

Materials needed: New horn setup, stock horn w/ bracket, about 3 ft of wire (2 colors preferred), splice nuts, wire terminals, 3/4" by 6" aluminum, various bolts, 20A fuse

How to do it..

Step 1-
Remove the grill. Very simple. Remove the two 10mm bolts on each end of your grill, then pull upward (yes pull, it won't break) and then out away from the car to remove the grill. There are several push pins that are pushed into the radiator support, so be sure to keep those for later on.

Step 2-
Remove the stock horn. Again, the 10mm socket will remove the bolt holding the bracket in place and save for later. Remove the wiring clip from the horn and the assembly should be free. Take an adjustable wrench (or a box wrench if you have one big enough) and flip the horn over. Remove the nut holding the horn in place and save the bracket.

Step 3-
Make the new bracket. The way I set mine up is quite simple, and still provided clearance to put the stock grill in. I took the aluminum (available at any Home Depot for about $3.25) and cut about a 5" long piece. File the edges to remove any burrs. My horns were mounted with square head bolts, which the horns slipped over. I then took the drill, spaced out the horns evenly, and drilled holes about 5/8" away from each edge and vertically centered on the aluminum. I then test fit the horns on the aluminum bracket. After removing the horns, I then measured to center, and drilled another hole in the middle of the bracket to attach to the stock bracket. (NOTE: you may drill a larger hole if you feel necessary, but I just used a washer to hold in place with a 1/4" bolt.)After drilling, I then found a bolt, 2 lock washers, and a nut to combine both brackets together. Bolt, washer, aluminum, stock bracket, washer, nut was the order which they went together. A drop of Loctite on this bolt is recommended. Next, remount the horns onto the newly made bracket.

Step 4: Install the air hoses. Since the horns are mounted on the bracket, start there. Cut the pieces to mount to the Y connector, and then you will need about an 8" piece for the compressor line. Mount the compressor line on the compressor, but not on the horn side just yet.

Step 5:
Mount the compressor. If you look with the grill off, in the center of the opening, there is a vertical beam. On the passenger side, there are some holes already made. I used one of these to mount the compressor. I first threaded the nut and bolt by hand, then mounted the compressor, and tightened it down. My compressor was smaller than a pop can, just to give you an idea of how big, and it is also inverted. I mounted it with the air nozzle pointed directly to the passenger side to avoid kinking the air lines, and since the wiring terminals are on the bottom, make wiring easier.

Step 6:
Mount the horns. Using the same 10mm bolt you removed originally, mount the new bracket with horns in the stock horns location. They should fit without any problems. Connect the air line to the Y fitting on the horn side and the plumbing and fabrication are all done. Check for kinks in the compressor line, and rotate the compressor as necessary to remove the kinks.

Step 7:
Wiring. First, pop the fuse box cover off inside the engine bay. Remove fuse 13 (15A) and replace it with a 20A fuse. If not, you will constantly blow the fuse as soon as you hit the horn. After that is changed, clip the stock horn terminal off, and strip the wire back. You will need to splice into this wire for +. Connect this wire to the + side of the compressor using a terminal. Next, use another terminal to connect to the negative side of the compressor, and run it to a chassis ground. I used the passenger side bolt of the hood latch for mine, and put a ring terminal between the bolt and radiator support. At this time everything should be connected. Make sure when wiring that you either tape or shrink tube the connections as they will be subject to water, snow, and all that good stuff.

Step 8:
Enjoy your horns! Mine are great and I love them. They can scare people but are loud enough to mean business on the highway. 134dB is good enough for me.

I will post pictures soon.

Feel free to comment.
 
Ha, that would be interesting. I should have pics up in the next 48 hours. I did the install over 2 days, so I will take the system back out and show the pictures to make the how-to easier to understand.
 
I found your post first when I was installing mine, but since there was more involved, I decided to write up my own how-to. The horns I bought were only 27.99 from JC Whitney, and theyre great.
 
cool beans

Nice write up Steve,

So, was it the blown fuse that kept the horn from working on saturday? Gald to see you got it figured out. Look foward to hearing them on Saturday!

-Tom
 
nice write up man.
I did practically the same thing, only I didnt wire into the stock horn wires. I just ran separate push-on switch into the cabin (mounted it into one of the slots where coin holder used to be next to dimmer control. Plus I also replaced stock horn with Fiamm Low tone horn and added Fiamm 128 db air horns (heavy duty compressor)

p.s.
moved to 3rd gen. 'how-to' section
 
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No, when I first wired it up the chassis ground I used came loose and I got frustrated and was getting ready to head out, so I didn't bother to fix it. The next day I sat down and thought it through and hooked it up and it worked on the first try. Thanks Tom for filling me in on the 20A fuse swap out, I haven't blown the fuse yet.

I'm hoping either Weds or Thurs. for pics, just gotta find time between school and remodeling our kitchen.
 
The only thing I'd worry about is the fuse swap. The wiring in the circuit may not stand up to the 20A that the fuse will. Since the horn circuit is a low-use circuit, you may never have a problem. If you do burn up a wire, you'll have to replace it all the way back to the horn relay.

When I set up my horn system, I laid in a whole new wiring harness with relays and arming switches and used the stock horn wire as a relay signal. The air compressor pulls a constant 12A with a surge even higher, so I didn't have much choice in the matter.

http://www.msprotege.com/forum/showthread.php?t=70143
 
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goldwing2000 said:
The only thing I'd worry about is the fuse swap. The wiring in the circuit may not stand up to the 20A that the fuse will. Since the horn circuit is a low-use circuit, you may never have a problem. If you do burn up a wire, you'll have to replace it all the way back to the horn relay.http://www.msprotege.com/forum/showthread.php?t=70143

thats the reason why I wired my air horns separately from stock horn, hehe
 
That is one thing that I did wonder about, however I've talked to others who've installed them this way and not had a problem. Although theyre not quite as loud as yours Kane, I can still scare the s*** outta people with them.

I think as long as youre not laying on the horn for minutes at a time, the wiring SHOULD hold up.
 
Actually, on the subject, the horns I purchased came with a relay and instructions on how to wire it using the relay and a 20A direct line from the battery. That would also be an option. I wrote the how-to moreso to give people an idea of how to successfully mount the horns without cutting anything to make them fit. When it comes to wiring, there are tons of different options to make it work, just like mentioned above. It's all in how you want to do it.
 
yep, i did my air horns instalation according to a diagram. Plus in New Jersey, if DMV inspection hears that you have air horns as stock horns they will fail you......lame s***. Thats one of the reasons why I have air horns separate from stock horn.
 
that really is some lame s***. I would think they would like that more since they are more of an alert than our stock horn is. But then again im not the DMV

DiS said:
yep, i did my air horns instalation according to a diagram. Plus in New Jersey, if DMV inspection hears that you have air horns as stock horns they will fail you......lame s***. Thats one of the reasons why I have air horns separate from stock horn.
 
highrollinpro said:
that really is some lame s***. I would think they would like that more since they are more of an alert than our stock horn is. But then again im not the DMV
yea dude its really stupid. Im guessing its because of higher db levels that air horns produce over stock horns......dunno. I know for sure that my air horn is loud as ****. Scaring people in front of me is my favorite, especially when they are driving 15 mph slower than speed limit on a major highway, heh.
 
I love driving through campus and waiting for people to walk out in front of me, as soon as they do that, theyre toast. I've had some golden opporutunities in doing that in the past 2 days, and ive a lot of people laughing when I scare a few of them.
 
highrollinpro said:
Actually, on the subject, the horns I purchased came with a relay and instructions on how to wire it using the relay and a 20A direct line from the battery. That would also be an option. I wrote the how-to moreso to give people an idea of how to successfully mount the horns without cutting anything to make them fit. When it comes to wiring, there are tons of different options to make it work, just like mentioned above. It's all in how you want to do it.

Using the relay and a direct line from the battery may even make the horn louder because you'll be able to get more juice through a bigger wire. More juice will spin the compressor faster.
Faster spin=more psi, more psi=more noise (thumb)

That way you could also put a switch in the system to disable the air horns (if you wanted to).
 
goldwing2000 said:
That way you could also put a switch in the system to disable the air horns (if you wanted to).
Dont really have to. Thats what the separate switch/button is for (wink)
 
highrollinpro said:
C'mon, who would want to disable these fantastic air horns?
man has spoken, haha. NO ONE WOULD WANT TO! besides cops and DMV people, haha
 
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