I'm attempting to hookup the argofet to a Mercruiser Alternator part #863077-1. there is the large output charging post and a plug with 2 wires, 1 purple, 1 pink and green? The unit is not showing any charge so I assume it is not getting "excited". Where should I attach the B+ wire from the Argofet to? Instructions say B side of alternator. I am unable to determine which wire is that. additionally if I identify the correct wire do I cut it or spliced into it leaving it connected?