Generator fuel pump or similar running when turn 12V off

[twvette]

Another dealership "mis-communication" ...

When I picked it up new they did not have the heavy gauge generator (Onan 5500) power attached directly to the battery and did a bit of a hack job with bolt wrapped in electrical tape to connect it to another smaller cable that went somewhere else. When I inquired about this they said "Keystone recommended this so the generator would not randomly try and start itself" and that it was routed to the 12V disconnect switch (far away from batteries). Seemed like very strange reply/solution to me. I just asked them to clean up the connection with a real power distribution block and heavier gauge wire when took it back in for various warranty service.

When I picked it up from service they had just connected the positive back to my battery bank claiming this is what I had requested when it was not. Everything worked fine so did not think it was going to be an issue and back to how it would typically done. However, later realized when I turn off the 12V power to the entire hauler via the standard disconnect switch I hear something running/humming in the generator so I assume this is the actual issue the dealer was trying to resolve. It sounds to me like its the fuel pump but not sure. It is not trying to start itself. It will stop after a couple of minutes but I am not sure if it might randomly also be doing this when sitting in storage. Anyone aware of this issue or can make any sense of it? Is it really the fuel pump or maybe something else that is "normal"? I do have the In-Command system but since its powered off when 12V is off I don't think it could be doing anything but maybe it just triggers this one event when it loses power.

I am considering using a separate generator starter battery so maybe I will just do that and see if it also resolves this too, but just curious why the generator might be doing this in general.