Bummer!
Could be hard to trace if in a wiring bundle. First, call Hunter and ask for help. Second, check with meter at the float switch which is where the 12 volts should be ALL the time. If no 12 volts there then see if you can find a smaller gauge wire(10 or 12) near the battery terminals or main battery switch. Maybe it just came disconnected. This assumes an H31 always has 12volts to the pump, that it does NOT come from the panel. On my boat(H37C) the wire goes from the float switch through a bundle in the bilge, through the engine bay, and directly to a battery post. The H30 is that way also. Let us know what you find.