Originally Posted by JDByrider1
Is it possible that the on demand switch be located in the Shurflo 2088?
Yes, there is a switch inside the pump that starts pumping when the pressure goes down, like when you turn on a faucet. You do need 12 volt power to the pump terminals before the internal switch will turn on the pump to draw water from the fresh water tank.
There should be an external switch that will send 12 volts to the water pump terminals. The pump will turn on and start "pumping" even without freshwater. Letting the pump run while dry is not good, it can end up overheating. Earlier you said you tested it with a battery so I presume you were testing it dry just to see if it spins. Mounted in the camper it would also spin IF
power is getting to the terminals.