Have they ever worked for you? Could be operator error, a blown dc breaker for the pump motor, a blown fuse for the pump motor solenoid, a bad ground. Brand and model of jacks would help.
2006 Damon Daybreak 3276 35'with 5 Star Tuner. 3 200 Amp Lithium batteries and 2000 watt PSW inverter/charger. 2013 Elantra on a Master Tow dolly.