Alternator warning light circuit

[Minto09]

I have a late 2002 Swift Kon-Tiki on a Ducato 18 JTD . Swift attach the signal /command power supply for it's relays to the above Ducato circuit up from the alternator. The Swift wire has become detached but as both wires from the alternator have scotch-locks on them, I don't which one it was linked to. The wires are both a grey/green colour, one has a yellow stripe. Any ideas which one I should use. cheers