The lighter idea works. I have plugged in a wire from the tach lead (or coil) to the lighter hot, when the button is pushed in, it grounds the element. As for fuel, check into fuel tank selectors for a truck with dual tanks. Wire it so it is open when 'hot', and cap off the other inlet. Haven't tried a switch inline the the power going to the control unit, but it should work. BTW, who notices an extra dimmer switch on the floor, maybe a little higher up the floor? Also used to have a flashing light under the dash that lit the floor up a bit, it was noticeable when beside the vehicle, but not too obvious.