You checked there is actually any voltage at the horn connections? Lidl ( i think) are knocking out a cheap car voltage checker thingy m gingy this week on the cheap.Same as mate mine just stopped and wont work changed it and fuses and got no result
Are you sure? I've got a 2.4D and it has deffo got a Relay 53 ... which i'm led to believe is for the horn? Additionally I can only see one horn under my bonnet.Only Caravelles or models with two horns have a relay.