If we are talking about the regulator on a 600Ss it should be a single phase one with the two Yellow wires and look a bit like this one here
https://regulatorrectifier.com/catal...ges/EDL450.JPG I can't recall which fuse is which as with the 5 looms I have modified so far I have done away with the box as well the large connector that joins the front harness to the main harness, Also done away with lighting wires, indicator wires etc