Originally Posted by eric-the-red

You can wire in a fuel cutoff switch so it automatically cuts the power to the pump every time you turn the vehicle off, that's more convenient than setting it each time, or forgetting it each time as I tended to do. You just put a normally open relay in the circuit, with a hidden momentary contact switch to close it. Then connect the relay output to the coil input to keep it closed as long as it has power. As soon as the power is interupted the relay opens again, and cuts off the pump.