The Chevrolet Spark side marker requires a 7443 bulb size for proper installation and function within the lighting assembly. Data for the specific component covers the range from 2013 to 2015.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Chevrolet Spark front side marker position uses two distinct bulb types across its model years: the 12961 for 2016-2020 and the 7443NA for 2013-2015.
The 12961 is a Philips part number designation for a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12V and 5W.
The 7443NA is an ANSI-standard T20 dual-filament wedge bulb with natural amber glass, rated at 12V with a 21W main filament and a 5W secondary filament. The amber tint is built into the glass rather than applied as a coating.
The T10 and T20 designations refer to the outer width of the wedge bulb in eighths of an inch, making the T20 physically larger than the T10. These two types are not interchangeable with each other.
The rear side marker position on the Chevrolet Spark uses the 7443 for 2013-2018, a clear T20 dual-filament wedge bulb rated at 12V, 21W/5W.
The 7443NA used in the front position and the 7443 used in the rear share the same T20 form factor and wattage ratings. The sole difference is that the 7443NA carries natural amber glass, which affects color output.
Substituting a clear 7443 for a 7443NA in the front side marker position would alter the emitted light color, as the amber output of the 7443NA depends on its tinted glass.
The 2019 Chevrolet Spark rear side marker uses the 7440, a single-filament T20 wedge bulb rated at 12V and 21W, rather than the dual-filament 7443 used in all other rear side marker years listed.
Although the 7440 and 7443 share the same T20 wedge base and are physically similar, the 7443 carries a second filament that the 7440 does not. Fitting a 7440 in a socket wired for dual-filament operation would result in only one circuit function being served.
The 12961 operates at 5W, considerably lower than the 21W main filament rating of the T20 bulbs used elsewhere in the Spark side marker positions, reflecting its use in a smaller, lower-intensity front marker application.