My first thought would be the relay for the horn. If your little beauty was wired up like my old V4 then...Fused line to operate relay - neutral/earth back to horn button. Direct line to be operated by relay to horn/s. Horn neutral to earth. My relay was fitted near side front (engine bay) attached to front grille support (along with the bonnet release cable).
This time the horn is still good found the ground trough the steering column is gone half way (crash safety? connection) so added a wire on this spot So it's solved.