Kelly motor controller control box

This is an odd little question. We recently got a kdz type controller for our marine application and one of kelly controls’ “controller accessory” boxes to facilitate messing about with same. Unfortunately, the thing came with no instructions of any kind and the part of kelly’s website that supposedly has wiring diagrams, etc, turns up a 404 message when searched. The thing has a 14 pin plug, which I’m assuming into the j2 control port, but it also has a lone, alligator-tipped wire that is obviously supposed to go, um, somewhere. Any ideas? Kelly has been less than forthcoming. Our system runs at 48v.