Faulty pressure switch on pump.
When you open a faucet the ON-Demand pump should start almost immediately due to the instant drop in pressure, same if leak occurred and no pressure in line.....pump would start build pressure.stop repeat when/if pressure dropped
Pump would cycle repeatedly within short amount of time if pressure dropped provided the pump PRESSURE SWITCH was working.
When pump does run how is flow/pressure?
2011 camper probably has a Shurflo Classic 2008 pump.
That has been discontinued so any parts would be Old Stock
Pressure switch can be changed but easier and not much more in cost to replace with a Shurflo Revolution 4008 (little higher flow and bit higher pressure 3 gpm/55#)
