ST8002 Cable Sheared

[Brewster16]

My ST8002 has been able to provide an accurate heading at the moment I hit "Auto button" but that's about it. The autopilot is NOT engaged when I hit Auto button. Everything looks in order on SG2 course computer and all fuses looked fine. However when I looked at the back of the St8002 head unit the "NMEA IN + and -" connection cable is not there and I found a sheared off end of a cable down behind the head unit [censored] in the dash. I've attached 3 pictures for clarity. My questions:
1. Is this the likely source of my autopilot problem?
2. The connection looks like a spade connector to the + and - "NMEA IN". Is it?
3. What replacement cable do I need to buy?
4. What does it connect to on the other end? I have a Raymarine E120 MFD and a Searay Navigator MFD.
5. Or, does it connect to the autopilot SG2 course computer? (It's a mass of zip tied cables so I can't quite trace it)

Thanks,
Bob