If your Chevy Silverado's fuel gauge is not working properly, you can try resetting it. To do this, first turn the key to the On position without starting the engine. Then press and hold the Trip/Odometer button for about 10 seconds. The fuel gauge should then reset and start working properly. If it does not, then there may be a problem with the sending unit or wiring that will need to be diagnosed and repaired by a qualified technician.