401 Fuel Gauge or Sender Problem.

[innellan House]

1. I assume fuse between A3 and A4 terminals in voltage regulator is OK (i.e. turn signals, brake lamps, and other instruments all working)
2. If isolated gauge or sender failure....next check fuel gauge is earthed (gauge should illuminate at night when you switch on the lights). Also check it has been correctly rewired if it has been removed.
3. Verify that there is continuity between sender and fuel gauge.
4. And sender earth is good.
5. last possibility is sender wiper is making poor contact (clean the surface of resistor over which the wiper travels. Bend wiper to increase contact with resistor).

regards,
vincent