Trying to fit a new horn, help!

[gti jack]

Hi guys, I'm trying to fit a new horn to the G but am having a pain in the ass of a time

The old horn works fine, I'm trying to fit a nautilus horn (air compressor electric one, donet have big trumpets)
And the voltage coming to the supply on the horn is fine it's getting 16v
The feed from the battery is similar.
When I try to make the horn work it sounds like it's dying, it's not loud at all were as if I connect it to the battery it's loud.
I thought it could be the earth so I made a new earth and it goes off all the time now,  I'm pretty good with electrics but this has me ststmped
Any help would be great

[Weeman]

If memory serves me right the horn is fed with a permanent live from the battery (via fuse) and the horn button itself is the neg. Hence why you giving it a new neg is making it go off all the time. Measure the resistance to ground when you press the horn button and make sure its a good earth.

Hope that make sense

[gti jack]

I thought it could have been an earth, I'll try and follow it back and see were it's all earthed too