In the process of diagnosing my main problem, (see Q1) I discovered a water connection that leads no where. It is just a dead connection on the water tank trim cover. there are no un-connected hoses on the inside. Really appreciate it if someone can look at the attached photo and give me some info on where this feed should connect. It sounds like this is a connection that should feed water into the grey or black holding tanks to flush them out????

Sewer Flusher.jpg