How-To: Install Hella Sharptones/Supertones in a Mazdaspeed 3 or Mazdaspeed 6-2024 update!

Datamined from the old forum archive of my original post. Pictures unfortunately did not survive.
Good starting reference:
How To: Install Supertones - NASIOC

2. Disconnect one of the factory horns (or both if you desire). Don't cut the connectors, you will need to use one of them later.

3. Look at the relay that came with the horns. The terminals are numbered, this is what those numbers mean:
87 - (+) Lead for the supertones/sharptones.
86 - Where the stock horn wire conects.
85 - Relay ground wire.
30 - (+) Power wire, connects to the battery with a fuse.

4. Figure out where you want the relay, because that's going to decide on how you run the wires. Once you have that figured out ...

5. Use your 14G wire to make a harness for the #87 to go to the horns. I ran one 14G wire to one horn, then spliced the second horn with a vampire clip. At all three ends, I used 14G female connectors.

6. Take some 14G wire and crimp a 14G male connector on it. Plug this into one of your disconnected factory horn wires. Then put a female connector on the other end and plug it into terminal #86on the relay.

7. Find a suitable ground and wire up #85 on the relay. I used a stock ground location next to the batery (see pictures).

8. Now, you need to ground the horns. I ran the ground to the passenger side ground location (see pics). I also made the exact same kind of wiring harness for the ground wire as I did with the (+) lead from the relay.

9. Last is making the connection to the battery. I used a ring terminal and conencted it right to the battery and ran the wire through the protective cover for a clean look. This is where you need to use a 20A fuse terminal.

10. Install your fuse into the fuse terminal and test your horns.

Wiring Setup



2024 update! I purchased a relay harness on Amazon as my original relay died. Well it's now stupid easy. Like wow easy. It's all there.

Get this.
https://a.co/d/ekW8bmv

And follow the layout. I then tucked
the harness into the CorkSport 51r battery box.

 

OK update 2024! I purchased a relay harness on Amazon as my original relay died. Well it's now stupid easy. Like wow easy. It's all there.

Get this.
https://a.co/d/ekW8bmv

And follow the layout. I'll be taking pics tomorrow. I have it connected and tested. Hoping the harness will fit in the CorkSport 51r battery box.