spare connector where does it go?

Hi just put new gearbox into my diesel but when putting wires back on I've one left over, can someone tell me where it goes please? It's the one near the middle of the pic, sleeved onto the big lead coming from the battery.



Thanks very much.

starter motor if it comes from the positive terminal.

Jon.

I already had one on the starter, but thanks for reply. Turns out this connector was not actually wired in to the positive lead from the battery.