My cousin picked up a box of Mitsuba Turbine Truck Horns from Japan and he gave my brother and I a pair to replace the tiny stock horns with something with a louder and more noticeable sound. The kit includes one high tone (SH-1) and one low tone (SL-1) plus some universal mounting hardware and a cheap relay kit. Originally I thought about just doing a straight swap, putting the new horns in the stock horn location, but once I saw the horns in person and compared them to the OEM horns, there was no way that would happen.

Can you tell which horns are the aftermarket ones? Hint – they’re much larger than the OEM horns.
In case you were wondering what it looks like inside, if you take the covers off you’ll see this.

I figured out a spot in front of the radiator where I could actually fit both horns using the included mounting bracket – and there happened to be a threaded bolt hole on the radiator support that lined up perfect for me, meaning I did not have to bring the drill out. I did have to modify the horns and the bracket a little bit to gain some badly needed forward clearance.

Mounted up front with the horn ends facing down to prevent moisture getting trapped inside.
Here’s a side view. Note how the size of both horns are really pushing the limit of space up front – and this is still without the grill back on.

Switching to a different part of the upgrade, I checked specs and found that the OEM horn relay was rated at 15-amps. That’s not bad, until I realized that the two new horns combined pulled almost 20-amps. The solution was easy – install a dedicated 30-amp horn relay, which I did behind the radiator support. I had 12v+ directly to the battery, and the coil was connected to the OEM horn wire.

12v 30-amp relay installed on the inner side of the radiator support for protection.

With the wiring done, the moment of truth was reinstalling the front grill. Turns out that I had repositioned the horns just right, as they barely cleared the inner portion of the center grill. Now I have a much louder horn (er, horns) that make a truck sound more like a truck, and not a Nissan Versa or something.

Squeezed in with a pinch of clearance behind the center grill.
You won’t know they’re there unless you peek through the center grill.