Join Date: Oct 2006
Location: Green Bay, Wisconsin, USA
Make: GL1500 SE
If your other gauges seem to be off you might check the instrument voltage regulator. (IVR 7 Volt) If only the gas gauge you probably have a dirty or bad sender. The third possibility would be a bad connection in the gas gauge circuit. At the sender you should find 2 wires.. The green needs to be a good clean ground. The yellow/white needs to have a nice clean connection also. If you short the yellow/white to ground briefly with the key on the gauge should swing all the way in one direction. When you disconnect the yellow/white the gauge should go all the way the other way. Those 3 are most likely but it might be an issue with the gauge itself.
Worked on the "big rigs" for 45 years now just riding my Wing whenever I can. Gets cold in Wisconsin.