Hey wodniw5 check out this self test. If I recall correctly, an open circuit makes the gauge read past full and a closed circuit with no resistance reads empty. So disconnect the sending unit wire from the sending unit. Still half tank reading on the gauge? Then either there is electrical connectivity elsewhere or the gauge is faulty. How about removing the gauge cluster from the dash so you can access the terminals? Use a jumper wire from sending unit terminal to ground. Still no response then check the other wire. Either way, connecting to ground or no continuity in the circuit makes the gauge read to the extreme. Before you blame the gauge though, check the wiring. Use jumper wires if you have to, to simulate the wires in the harness.
Joe
