The FSV is mounted on the frame under the drivers side, and it is where your fuel lines from your tank are going. There is a 5 wire plug going into it. The 1st and 2nd wire are for the motor (polarity reverses to throw the switch) The 3rd, 4th, and 5th wires constitute a single pole double throw switch, the exact pinout of which I cannot recal, but you can figure it out easy enough by throwing the switch back and forth. One pin is the hinge, and the others are the front and back (relay terminology there). This relay is what feeds your fuel gauge info from the appropriate tank.
