1. Water in the tank.
2. Inlet valve to the pump open.
3. Winterization valve closed. This is the one used to suck anti-freeze from a jug and pump it through the system.
4. Check the fuse for the water pump.
5. Trailer battery fully charged or trailer hooked up to shore power.
6. On-demand pressure switch could be stuck in the "open" position.
7. Possible bad rocker switch at the control panel.
8. Open a faucet.
The drop in pressure in the lines will cause the pressure switch on the pump to close supplying 12VDC to the pump motor. When you close the faucet, line pressure rises to the pressure switch setpoint. The pressure switch opens and voltage to the motor will cease.
This should get you started on your troubleshooting journey.
2006 23B Hybrid with 10k round bar WDH
2011 F150 4x4 SCREW Ecoboost, Max Tow, Integrated TBC, 3.73 LS axle, Firestone Ride Rite airbags.