surely the problem occurs by people sticking a larger fuse in there because it blew?

i'd imagine if ford used 10A wiring there'd be a 10A fuse?

folk get pissed off with it blowing and stick a 15a one in and its fine for a bit

then it gets a bit more worn then a 20a one goes in

etc untill the wiring melts?

the relay is the cure but the fuse is there to protect the wiring so i cant see why it would melt assuming no-one ghetto upgraded it