The Kia Forte5 brake light uses a 2357 bulb size for the specific lighting components located at the rear of the vehicle. Data for the bulb specifications covers the range from 2014 to 2018.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Kia Forte5 uses two distinct bulb types across its brake lighting system: the 2357 for the main brake lights and the P21W for the center high mount stop light, covering the 2014-2018 model years for both positions.
The 2357 is an ANSI-standard dual-filament bulb rated at 12V with filaments drawing 26.9W and 8W respectively, mounted on a BAY15d bayonet base.
The dual-filament design of the 2357 allows it to serve two lighting functions from a single bulb, with the higher-wattage filament typically handling the brake signal and the lower-wattage filament handling the tail light function.
The 2357 is a brighter variant of the 1157 bulb. While the two share the same BAY15d base and are physically interchangeable in many sockets, the higher output of the 2357 means substituting a 1157 in its place results in reduced brake light brightness.
The main brake light application of the 2357 on the Kia Forte5 is conditional, applying specifically to vehicles equipped with halogen capsule headlamps.
The P21W is an ECE-standard single-filament bulb rated at 12V and 21W, mounted on a BA15s bayonet base, and is used in the center high mount stop light across all listed model years.
The 2357 uses a BAY15d base while the P21W uses a BA15s base. These two base types are not interchangeable, as the BAY15d features offset pins to accommodate dual-filament orientation while the BA15s has a single-contact design.
The P21W follows ECE regulations common in European and worldwide markets, whereas the 2357 follows ANSI standards used in the United States and Canada, reflecting a mixed-standard fitment across the Forte5 brake lighting system.