How do you repair a nonworking fuel gauge to a 1966 Plymouth Valiant?

To repair a nonworking fuel gauge in a 1966 Plymouth Valiant, first check the gauge itself and the wiring for any visible damage or corrosion. Next, inspect the fuel sending unit in the fuel tank for proper functionality, ensuring it is not stuck or faulty. If needed, replace the sending unit and ensure all connections are secure. Finally, test the gauge by turning on the ignition to see if it registers correctly.