Fuse keeps blowing

So there is a short with the back-up lights that need to be tracked down. Start by looking at the back up light bulb sockets, and the wiring behind them.

What are they

I'm in the U.K. Don't know if there different

this help me with my 2000 focus ZX3 , please check the wire for the reverse switch at the transmission it could be touching a metal, normaly this wire have a wire protection that is good for heat ,but with the time it could just fall in part, in my case this was happening and after i visually inspected ,no protection and the wire was touching a metal bracket that for sure turn really hot,after i protect the wire again, no more fuse blow when reverse(i blow 3 troubleshooting the issue) hope this hel