Is the pump voltage the same as the battery voltage? I think we could be jumping to a conclusion too quickly. Could be a low battery. Or could be the something else. Seems to me if you are boone docking you would know if your battery was down. Is there a voltage drop between the battery and the pump? If you have a voltage drop between the pump and the battery I would disconnect it and connect it directly to the battey. cannect a short piece of hose to the input and stick it in a pan of water to see if it pumps. if it pumps water connected to the battery then it could be a clogged line putting a load on the pump or a bad electrical connection. You have to isolate the problem. Could very well be a battery problem if your battery voltage is that low.