How to install an ultra loud horn the right way

When you have a small motorcycle like my honda dax. You might want to compensate a bit to make people recognize you’re there. I already installed extra lighting as you can read here. Add to the mix that I live in Amsterdam (a crowded city) and people are constantly checking their phones whilst they should be driving. And you can imagine that I absolutely need a good loud horn to make people aware that I’m here. Luckily we have our Chinese friends from AliExpress who never disappoint. They have a super loud horn that’s small enough to fit almost anywhere. And that for under €20. Let’s install it together!

Ultra loud horn
This is the 12V horn. Really loud and relatively small so it can always fit somewhere on your desired project. Order it here

Mounted loud black horn

I ordered and installed quite a few and they always seem to have only red in stock. Since mine will be hanging outside. And I don’t want to stand out, I painted mine black. I Also chopped some plastic bits off so that my suspension has enough space to operate properly. Be careful that you only chop of plastic, and don’t make holes in the actual horn itself.

For the mounting itself, I just used a piece of scrap metal plate and found a bolt that had some room to fit my metal plate under it. Drilled a hole in the plate so it fits over my bolt and it hangs. If I hadn’t had a piece of metal I would’ve used wood (paint it first so it is weatherproof). I mounted the horn with the electrical contacts facing downward to avoid getting water in there.

Because this horn is super loud, it uses a lot of electricity (15A if you believe the user manual). When using a lot of electricity it’s likely that the wiring of your old horn installation isn’t sufficient enough. That’s why they included a relay. With this relay, we can use the same horn button as we already have but we provide the electricity for the loud horn direct from the battery. It looks something like this:

Schematic overview of horn installation
Red is obviously the positive wire, black the negative wire. The relay replaces your old horn so find a place to hang it somewhere weather-resistant and safe from other outdoor exposures.

As you can see in the picture above the relay comes instead of your old horn. When the relay gets 12V (when you press the horn button) it will connect the plus wire that comes from the battery to your horn. The negative wire can go straight from your battery to the new ultra loud horn. The relay has numbers on it, the scheme on top of that explains what it does.


This scheme tells us that when 85 and 86 have a circuit (that happens when you press the horn button) it will connect pin 87 with 30. So that means

85 & 86 are for your old horn wires (plus and min doesn’t matter)

87 & 30 are for your plus wire from your battery to the new horn (doesn’t matter which of both pin you choose )

Run electrical wires (the thicker the better) from your battery. Remember, the – goes directly to your horn The + goes to your relay on pin 87 or 30. Give the + a 20A fuse as close to the battery as possible (too close to the battery would make it impossible for me to close my seat). Make sure the wiring is safe and won’t wear out over time and eventually short circuit, might want to give it some extra protection here and there (tape). Give the wires the right plug connection to connect to the battery, relay, and horn and you’re good to go. I’ll provide a link with the required materials below if you don’t already have them.

Fuse holder

Fuse holder, choose the option with the 20A fuse. Order it here. You can solder this between your plus wire using our soldering guide

Electrical tape

This is the electrical tape that can protect wires against rough conditions like shaking motorcycles. Order it here

Crimping terminal

Crimping terminal to connect your wire to your battery, I needed M5 for my battery. Check your battery what bolt size you need for your specific project. Order it here

Crimping terminals to connect the wire to the relay and horn. You’ll need the blue 6.8mm one for this project. Order them here

Crimping pliers

Crimping pliers to make the connection to your horn and relay. Order it here, choose the option with 4 jaws since you need the “02C jaw”.

It’s 2021and some people are still afraid to order from China. If you’re one of them, read our guide: is aliexpress reliable: a beginners guide

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