The fuse is fine and the horn still working but the Sat nav did not register it was charging when wired to the horn but did when put straight on to the battery, is there any reason why this might be? I just thought that it would be 12v and work yet it seems to get more complicated? If I can't wire in a Sat nav then I will never get my project bike, Pan euro st1100, on the road!!!!!!!!! Agh!!!!