Are all other 12v items working? Can you hear the pump running when you open a tap. Swift pumps sound like a Jack hammer usually?
If you can hear it, try plunging the filter end of the external “pump” up and down in the aquaroll in case you have an airlock.
If the van is new to you rather than brand new then check the filter end of the taps are not clogged up with limescale.
Mel