Trying To Build A DIY Two Tone European Horn Siren

Greetings all,

Let me start by saying that I am brand new to the forum, searched and searched for this topic but found nothing and I’m not sure I listed this in the correct category so I apologize if I got anything wrong.

I’m trying to make a 12 volt, two-tone European horn siren using two Seineca 12 volt, 3 amp horns (different HZ/frequency tone). I’ve tried using a 20 amp headlight flasher to no avail. I have no clue if there’s an automatic switching unit that will work for this or if I will need to build something from the ground up. I know it’s possible since this type of siren already exists in the UK and other European countries but after conducting endless searches online, I only found one company that produces the air horn version and that system won’t work for this. Plus, a used air horn version two-tone siren runs $400 and up, I’m definitely not willing to spend that kind of money for a golf cart siren, even if it’s used for emergencies (fire/EMS).

You will need to use a solid state flasher and 2 standard Bosch now Tyco SPDT relays. Connect one siren to 87, the other to 87A. 30 of this relay will go to 87 of the second relay. 30 of the second relay will go to a fused power source capable of powering the sirens. Both relays, ground 85. 86 of both relays and the flasher are to be powered through the switch that activates the siren.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

I’m not trying to look a gift horse in the mouth but, is there a diagram posted anywhere online that shows this. I have never wired up a relay before much less two relays and a flasher. I’ve never been successful with SPDT switches so I’m not holding my breath that another attempt will turn out any different lol. However, I am definitely willing to give this a try.

Thank you “I am an idiot” for your response to my posting and I’m very grateful for the information.

This link will show you a relay and the terminals I mentioned. Draw 2 of them side by side and draw the wires from the terminals to the devices. Post what you come up with and I will verify it for you.

https://www.the12volt.com/relays/relaydiagram25.html

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

"I am an idiot", THANK YOU for all of your help. My apologies for not replying sooner but I was out of commission for almost two weeks and I'm just getting back into the swing of things. After trying two modern solid state flashers rated at 20 amps and having no luck, I dug out an ancient flasher my Dad had stashed from his Reserve Sheriff's Deputy days (1940's) and finally got everything to work !!!!. I can't thank you enough for taking your time to reply and offer your guidance.
I do have one last question. The alternating flasher switches back & forth a little faster than I['d like. It's not the end of the world but do you know any way to adjust this ? I included 3 pics of the flasher I used.

There is no way to adjust the timing.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

I understand. The timing will work just fine then and again I can't thank you enough for your help. I called my nephew to let him hear the results and he was quite impressed, lol. I have to admit, so was I.
Thank you once again and stay safe.