The fuel gage selector switch is a momentarily-closed-type switch. Contained within the fuel gage selector switch is a fuel indicator lamp (FIL). The fuel gage selector switch allows the operator to check the fuel level of either fuel tank-regardless of which fuel system is operating. The Alternative Fuels ECM monitors the state of the fuel gage select switch input circuit. When the fuel gage selector switch is depressed the Alternative Fuels ECM responds by operating the fuel gage relay. Operation of the fuel gage relay determines which fuel tank level signal is received by the Instrument Panel. The fuel gage will display the NON-OPERATING fuel system's fuel level for about 10 seconds after the fuel gage selector switch has been depressed.

The fuel indicator lamp (FIL) is contained within the fuel gage selector switch button. The fuel indicator lamp indicates which fuel system is in operation. The Alternative Fuels ECM controls the operation of the fuel indicator lamp. The fuel indicator lamp illuminates ONLY when the engine is operating on gasoline. The fuel indicator lamp will also illuminate for several seconds during start-up as a bulb check.