Toyota Corolla Turn Signal Bulb Size

Additional Notes

• The 7440NA and 7444NA bulbs share the same T20 wedge base and natural amber glass construction, but differ in filament count. The 7440NA carries a single filament rated at 21W, while the 7444NA carries dual filaments rated at 21W and 5W. On the Toyota Corolla, these two types appear across the same position in different model years, meaning the socket is physically compatible but the filament configuration differs between them.
• The 7443NA is also a dual-filament T20 wedge bulb with natural amber glass, rated at 12V and 21W/5W, making its electrical output identical to the 7444NA. Both the 7443NA and 7444NA share this dual-filament T20 format, though they carry different ANSI designations and are not confirmed as interchangeable by the specifications.
• The T25 wedge family, which includes the 3157NA, 3457NA, 3357NA, 3156, and 3156NA, is physically larger than the T20 family. The T25 and T20 bases are not interchangeable, so a bulb from one group cannot be substituted into a socket designed for the other.
• The 1156 and 1157 bulbs use bayonet bases rather than wedge bases. The 1156 uses a BA15s single-contact base, while the 1157 uses a BAY15d offset dual-contact base. These two base types are mechanically distinct, and the 1987 Toyota Corolla front turn signal specification reflects this directly, requiring the 1156 with halogen capsule headlamps and the 1157 with sealed beam headlamps.
• The 2356 bulb, specified for the 2001 rear turn signal, uses a BAY15d bayonet base, which is the same base type as the 1157. However, the 2356 is listed separately from the 1157 and carries no wattage figure in the specifications, indicating it is treated as a distinct part number rather than a substitute.
• The 2456 bulb is classified as a festoon type for specialty applications, which differs structurally from both the wedge and bayonet bulbs used elsewhere in the Corolla turn signal system. It is rated at 12V with no wattage listed in the specifications.
• The 2016 Toyota Corolla front turn signal position carries two separate entries: the 7444NA for production built up to August 2016, and the 7440NA for production built from August 2016 onward. This mid-year production change means that two vehicles of the same model year may require different bulbs depending on their build date.
• The "NA" suffix present on many bulb designations, such as 7440NA, 3157NA, and 3156NA, denotes natural amber glass coloring applied to the bulb envelope itself. The non-suffixed equivalents, such as 7440, 3157, and 3156, produce clear light. Substituting a clear bulb for an NA-designated one may not meet amber output requirements for turn signal applications.