The Fiat 500L turn signal requires a bulb with the unique size of P21W for proper operation. Data for the specific component covers the range from 2018 through 2018.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Fiat 500L uses two distinct turn signal bulb types across its front and rear positions: the 7440NA for the front and the P21W for the rear, covering the 2014-2020 model years for both positions.
The 7440NA is an ANSI-standard bulb, meaning it conforms to North American specifications used in the United States and Canada.
The 7440NA belongs to the T20 wedge family, a single-filament design that seats into a wedge-style socket without a separate base component.
The "NA" suffix in the 7440NA designation indicates natural amber glass, meaning the amber color is built into the bulb envelope itself rather than produced by a clear bulb in a colored lens housing.
The P21W follows the ECE standard, a regulatory framework used in Europe and most international markets outside North America.
The P21W uses a BA15s bayonet base, a single-contact fitting where the bulb locks into its socket with a quarter-turn rotation.
Both the 7440NA and P21W operate at 12 volts and consume 21 watts, making them electrically equivalent despite their physical and regulatory differences.
Because the 7440NA uses a wedge base and the P21W uses a BA15s bayonet base, the two bulb types are not physically interchangeable with each other.
The single-filament construction of both bulbs means each is dedicated solely to the turn signal function, with no secondary filament for an additional lighting role such as running or brake light duty.
The use of different standards for the front and rear positions on the Fiat 500L reflects a split between North American-spec components and internationally-spec components within the same vehicle.