it's luminous green right? that's the ac stuff

fire up the car and turn the ac on and see if it comes on (or the ac actually works at all)

but now i've seen the pic it's deffo the ac pipe, it's the one that goes to the reciver/drier by the looks of it and if you get an aftermarket replacement they don't tend to line up in the holes that ford have made for them so it's better to go original (but they are 4x the price)