Hyundai Elantra Brake Bulb Size

Additional Notes

• The 2357 bulb is the most frequently specified brake bulb across the Hyundai Elantra's brake light history, appearing in the rear brake position across multiple model years from 1999 through 2021. It is a dual-filament bulb rated at 12V, 26.9W/5W, and shares the BAY15d bayonet base with the 1157 but operates at a higher wattage on its primary filament.
• The 1157 bulb is the second most common rear brake specification in these records. It uses the same BAY15d bayonet base as the 2357 but runs at a lower 21W on its primary filament. While the two bulbs are physically compatible due to their shared base type, the wattage difference means they are not direct equivalents in output.
• The 2357 and 1157 bulbs both use the BAY15d bayonet base, which positions them as dual-filament types serving both brake and tail light functions from a single socket. The 921 and 12961 are single-filament wedge bulbs and are not interchangeable with either of these bayonet-base types.
• For the 2020-2021 Hyundai Elantra, the rear brake position specifies the 2357, while the center high mount stop light uses different bulbs across those same years, indicating that the two positions do not share a common bulb type within the same model year.
• The PY21W, specified for the 2023 Elantra center high mount stop light, is the only ECE-standard bulb in these specifications. It uses a BAU15s base, which is offset compared to the BA15s base of the 1156, making it physically non-interchangeable with other single-filament bulbs listed here despite sharing the same 12V, 21W rating.
• The 7440 is a single-filament wedge bulb rated at 12V, 21W and appears in the center high mount stop light position for the 2014-2015 and 2019-2020 model years. It is not interchangeable with the 1156, which shares the same wattage but uses a BA15s bayonet base rather than a wedge fitting.
• The 12961 is a Philips part number designation for a miniature T10 wedge bulb rated at 12V, 5W with a W2.1x9.5d base. Its specification in the inner brake position for the 2021 and 2023 Elantra reflects a significantly lower wattage than all other brake bulbs listed, consistent with its use in a supplementary rather than primary brake light role.
• Several rear brake entries from 2014-2020 carry headlamp configuration conditions, such as "With Halogen Capsule Headlamps" or "Without Projector-Type Headlamps," indicating that the applicable brake bulb size for those years is contingent on the headlamp type fitted to the vehicle.