I had a similar issue on my 2015 Chateau. The water pump is next to the water tank under the rear BR mattress for my model. I tested all the power to the pump and everything looked good. The pump actually has a switch attached attached to it that checks the pressure in the supply lines. Once the supply has enough pressure, it will turn off the pump. I started wiggling the power wires to the switch and the pump kicked on.
Turns out the electrical connector, located at the bottom of the switch (poor design), had corroded and was not making a good connection. I switched out the connector and the pump is working great now.
Sounds like when you bounce on the floor it makes the connection and the pump is running.