Fuel Indicator Lamp Always On - Alternative Fuels

CIRCUIT DESCRIPTION
The fuel gauge select switch assembly contains two components. The fuel gauge select switch is used to indicate to the AF ECU that the operator of the vehicle has requested the fuel gauge display the level of fuel for the DORMANT or non-operating fuel system. The fuel indicator lamp (FIL) is used by the AF ECU to indicate to the operator of the vehicle which fuel system is in use. When illuminated the vehicle is operating on gasoline

The fuel indicator lamp (FIL) is supplied power by the ignition relay and the ground path is supplied by the AF ECU. The AF ECU will supply ground to the FIL for a two second bulb check at ignition ON during CNG operation or continuously during gasoline operation when the ignition is in the ON or RUN positions.

TEST DESCRIPTION

Steps 1-8:

Steps 9-10:

The numbers below refer to the step numbers on the diagnostic table.
1. The System Check MUST be performed before proceeding with this diagnostic table. Failure to perform the System Check will result in mis-diagnosis.
2. This step checks for proper operation of the FIL.
3. The FIL should only stay illuminated when the engine is operating on gasoline.
4. The GO Enable Input and GO Enable Output parameters both indicate the state of the GO Enable circuit. The Input parameter is the state of the enable circuit as monitored by the gasoline control module. The Output parameter is the state of the enable circuit as commanded by the AF ECU.