Kia Forte Koup front turn signal bulbs use 2357NA size while rear turn signal bulbs use 1156NA size. The replacement chart covers 2010 through 2016 vehicle production years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Kia Forte Koup uses two distinct bulb types across its turn signal positions: the 2357NA at the front and the 1156NA at the rear, with both types specified across the full 2010-2016 model range.
The 2357NA is a dual-filament bulb, meaning it carries two independent filaments within a single envelope, allowing it to serve more than one lighting function simultaneously, such as turn signaling and parking illumination.
The 1156NA is a single-filament bulb, dedicated to one lighting function, which is consistent with its placement at the rear turn signal position where a combined function is not required.
Both the 2357NA and 1156NA carry the "NA" suffix, which designates natural amber glass rather than a clear envelope with a standard filament. This coloring is built into the glass itself rather than applied as a coating.
The 2357NA operates at 12V with a dual-wattage rating of 26.9W on the high-intensity filament and 8W on the low-intensity filament, reflecting its dual-filament design.
The 1156NA operates at 12V with a single 21W rating, consistent with its single-filament construction.
The 2357NA uses a BAY15d bayonet base. The BAY15d designation indicates an offset dual-contact base, which physically prevents incorrect single-filament bulbs from being seated in its socket.
The 1156NA uses a BA15s bayonet base. The BA15s designation indicates a single-contact base, and this base type is not interchangeable with the BAY15d used by the 2357NA despite the similar physical appearance of bayonet-style bases.
Both bulb types conform to ANSI standards applicable in the United States and Canada, indicating standardized electrical and physical tolerances across manufacturers producing these part numbers.
Because the front position requires a BAY15d dual-filament bulb and the rear requires a BA15s single-filament bulb, substituting one for the other is not mechanically or electrically compatible, regardless of voltage rating similarities.