I missed the bit about the horn not working. :rolleyes The Pass switch takes its power directly from the 20A fuse headlight fuse and bypasses the relays and the right hand light switch. It proves the headlight fuse is working and the headlight main beams are working. The headlights in normal working mode have their own fuse and the signalling fuse switches on the 4 pin relay which runs power through the second 5 pin relay. This relay is used to switch from dims to heads.
Use a process of elimination. The 4 pin relay has nothing to do with the parking light or horn. Lift the tank and check all the connection in the black box. It sounds more like a corroded connection and since all the power and earths come back via connectors in that black box it is a good thing to check.
Use a process of elimination. The 4 pin relay has nothing to do with the parking light or horn. Lift the tank and check all the connection in the black box. It sounds more like a corroded connection and since all the power and earths come back via connectors in that black box it is a good thing to check.