Worked fine for me but I didn't use their schematic lol. I tried it didn't work, I don't know. I only used "ignition current" when the car was running, maybe that's the reason? I have a 5 year old and he loves horns. I attached the bases to the bottom and right posts. Then the ignition power is on the left or in the middle, and the siren is on the other side, on the left or in the middle. The top post was not used at all.
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