horn on constant

[chilly]

I'm a bit of a numpty when it comes to auto electrics.

Is there anything obvious which would cause the horn to sound of its own accord (there's current constantly to the purple wire at the horn).
The car has been converted to negative earth if that makes any difference.

I've checked for obvious shorts but can't find anything.

Cheers

Chris

[bmcecosse]

There is ALWAYS power in the lilac lead - the horn sounds when the horn push shorts the current to earth. If the horn is sounding - the problem will be with the horn push contacts.