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Discussion Starter · #1 ·
I bought this gem of a horn a couple of years ago intending to install it on my Yamaha R1 motorcycle. I sold the bike before I got around to it and the horn went into my Insight parts bin.... until 2 days ago.



1st- Search InsightCentral for examples and learn from other members' experience. The listing in the sticky thread is useful.

2nd- Choose an installation location. Up front in the grill area seems a logical choice. It's where the OEM horn is, but that single transducer horn is very small (hence the cute Road Runner sound it makes). The Nautilus is a dual transducer/waveguide unit and while it's a compact design, it's far too big for this location without doing some destructive modifications, which I was unwilling to do... for now.

The aluminum crossbar near the firewall, passenger side is a common location for installing aftermarket goodies, like cruise control, horn, etc. There's plenty going for it like ease of access, predrilled mounting holes, solid structure, easy access to the battery and ground, etc. I don't like this area for electronics since it's directly above the exhaust manifold, which is one the hottest parts of the car. The only item I would like to install in that area is a turbocharger, but that's not going to happen any time real soon. I found a space just below the 12v battery tray. The Nautilus has a single mounting bolt hole that fits an M5 screw and there's already a hole in the bottom of the 12v battery tray. Access is easy if your battery is slightly undersized (in width) and tucked in towards the passenger side.

3rd- Wiring. Some have wildly varying ideas on how wire things, with many examples of how to set something up temporarily but then stop since well... it works. This horn, according to the spec sheet, draws 18A of current. In order to use the oem steering wheel horn switch, a relay must be used to switch power to the horn. I wanted to be able to use both the oem horn and the Nautilus together, or at least have the option. I might consider wiring a switch in the dash to toggle between the two. Perhaps separate toggle switches for both, just for fun.



The steering wheel switch, when pressed, provides Ground to the horn relay under the hood via the orange wire. The other side of the relay coil is constant 12v+. When this relay is activated, it switches 12v+ to the horn. You can access the wire from the harness that leads to the fuse/relay box:



I spliced a green wire to the orange hood switch wire:


While not absolutely necessary, my wire splice has an inline rectifier diode to isolate the circuitry that I added from interfering with the normal functions of the car. In effect, the horn switch will activate both the oem horn relay and my added horn relay, but let's say the relay I added malfunctions- it will not cause the oem relay to activate.

Full disclosure: this is much easier to access with the driver side headlight lens removed, which also means removing the front bumper cover. This is a lot less dramatic than it sounds but it makes sense to wait to do this until you might have another reason to do so. In my case, it was a radiator and thermostat swap.
 

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Discussion Starter · #2 · (Edited)
Yes, I cut the wire to splice it. This is another way to verify you have the correct wire- the horn relay did not work after cutting it. I don't do ScotchLoks or other crimped splices- they are not reliable (IMO) and are far too bulky.




Splice done- ready to rewrap the harness and attempt to make it look unmolested:




The vast expanse of unoccupied space below the 12v battery tray:



Horn installed:

 

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Discussion Starter · #3 ·
Power to the horn relay requires it's own fused connection to 12v+. In addition to the horn, I installed a set of LED daytime running lights. I will need a 3rd 12v+ connection for an alarm system and a 4th will be for a battery charger.

So, now there's a new 4-way fuse box to handle that:




The underside made for a convenient place to mount the horn relay:




The 8 gauge wire taps onto the 80A fuse in the fuse/relay box with a ring terminal bent at a 90 degree.
 

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