Hi, i fitted a new aftermarket steering wheel and connected all the wires up on the boss ok with the correct ring and everything but horn is not working. I had swapped the loom round into my cab (s2 loom) and ive put one plug back on the horn that i labelled horn but i have a spare wire with a spade on the end of it that is black with white stripe and its next to the horn.Is this an earth for the horn,if not where does it go?

 

If no-one knows, does anyone know where the black wire with white stripe (has female spade connector on end) goes?