The sending unit is in the fuel tank so wherever the tank is located is where the sender is at. However -- why start diagnosis there when that process should start at the gauge. Do these steps in the order listed to avoid misdiagnosis. Verify that the gauge has +12 volts and ground with the key in the RUN position. If no -- fix it. If yes, then MOMENTARILY jumper the "S" (send) terminal to ground. If the gauge pegs full the gauge is ok and the fault is either in the pink wire back to the sender in the tank or the sender itself is bad. If the gauge doesn't peg, then the gauge is bad. Disconnect the pink wire at the gauge. Using an ohm meter, measure the resistance from the wire to ground. With 3/4 tank of fuel the gauge should read about 80 - 90 ohms. If no reading occurs, the sender is either open or the pink wire is open between the gauge and the sender. Now it is time to locate the sender.
