Working on my girlfriends Focus at the moment and noticed the horn wasn't working properly.

On inspection it just turned out one of the connectors was loose.

Being that is has one of those "dual tone" horns it has both a high and low tone. Strangely enough when I have both the horns connected up properly it sounded good and loud like they're supposed to, however when I bolt them to the horn bracket and tighten the nut on the back it doesn't seem to produce the "full" sound it should. If I loosen the nuts at the back however the sound returns to normal.

If it was one of those horns that has only a live wire and uses the bolting to the bracket as the ground it would make some bit of sense but these Fiamm brand ones have both live and ground wires.

Anyone able to shed any bit of light on this? I could leave the horns without bolting them to the bracket but I'm afraid they'll move around and get damaged

Stick some rubber washers between the bracket and fixing point.

Stick some rubber washers between the bracket and fixing point.

I'll try that mate. Could you tell me why that makes a difference though?

The vibration inside the horn funnels makes the sound louder.

Clamping it to a solid mount reduces the vibration therefore muting the sound.

Interesting, never knew that. Messing around with it again today and I've noticed if the horns are mounted to the bracket and the bracket is mounted to the car they sound fine while removing the bracket from the car with the horns still attached it sounds as if it's not receiving full power and the sound is greatly reduced and almost muffled sounding. I vaguely remember something like this happening on a previous audi of mine also