I see you also posted on the Hatteras Owner's Forum. There should be relay box in the ER that all the sensors feed into. Do a search there are a number of posts on the various system monitors over the years.
A good guy to call is Roger Wetherington, who worked at Hatteras for decades. He has all the different systems they used on hard board, and can walk you through it. His contact info is on this thread, one page back from where you posted:
12 Point Monitor Troubleshooting