2006 Ford F350 blown horn fuse

My started sticking on and then finally blew the fuse I have replaced with good fuse and can hear clicking that sounds like a relay but it is not any of the relays in the fuse block under the dash sounds like its coming from there? Or under the dash near there I have looked for the horn under the hood and can not locate it any where? So where do I fiind the horn it self or what should be the next step in trouble shooting this looking for your reply Gerry