Fuel Indicator Light
WARNING: This page is about a different car, the 2003 Pontiac Sunfire, 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, and 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
The Fuel Indicator Light (FIL) is contained within the headlight dimmer switch assembly. The FIL indicates which fuel system the vehicle is operating on. The Powertrain Control Module (PCM) controls the operation of the FIL. The FIL illuminates only when the engine is operating on gasoline. The FIL will also illuminate for several seconds during start-up as a bulb check.