Michael, if the gauge reads backward, don't sweat it. Take out the sender, bend the wire 180 degrees from where it is. That will reverse the movement of the wiper on the resistor and make your gauge correct. Measure the depth of the tank and eyeball where your float will be to adjust empty and full. I did mine with an empty tank and longer wires, tank out of car. It's a mechanical thing, don't change the wiring, ok?