DidHeFocus, Thank you for the excellent step-by-step instructions. And your decision to add these horns makes PERFECT sense to me.
With people listening to loud music with windows rolled up, they'll never hear the stock Focus horn...until a tragedy has unfolded.
One thing I'm wondering -- if you lightly tap the horn, does just the OEM horn make a sound, or do the air horns kick in? (It would be perfect if only the OEM horn is activated by a quick tap, because sometimes that's all you really want or need to do, is alert somebody in a not-overly-loud "tap-tap" way. But at other times when you KNOW somebody doesn't see you and they have their windows rolled up, you want to lean on it and blast it really loud!).
It's also great that by accident it works out so that the air horns aren't activated by the alarm's quick "beep-beep" confirmation. Again, you don't need/want that to be loud!
But my main problem is, this looks like too complicated an installation for me. I don't understand too many things in your explanation. Like, did you take the bumper off? I don't totally get it.
For clueless people like me, isn't there a non-air-horn MUCH LOUDER replacement for the OEM horn, that wouldn't require a relay, nor any additional wiring, nor any new mounting?