Scion tC front turn signal bulbs use 1156NA and 7440NA sizes, while rear turn signal bulbs use 7440NA and 7440 sizes. The replacement chart covers 2005 through 2016 model years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The two dominant bulb types across the Scion tC turn signal specifications are the 7440NA and the 1156NA, both rated at 12V and 21W and both classified under ANSI standards applicable to the US and Canadian markets.
The 7440NA is a single-filament wedge bulb in the T20 form factor with natural amber glass, while the 1156NA is a single-filament bulb with a BA15s bayonet base and natural amber glass. The two types are not interchangeable due to their fundamentally different base designs.
The "NA" suffix on both the 7440NA and 1156NA designates natural amber glass, meaning the amber color is built into the glass envelope itself rather than produced by a clear bulb inside an amber housing.
The front turn signal on the Scion tC used the 7440NA for the 2005-2013 model years, then shifted to the 1156NA for 2014-2016, representing a change in base type from wedge to bayonet for that position.
The rear turn signal specification lists the 7440 for 2005-2010 and the 7440NA for 2011-2016. Both share the same T20 wedge form factor, 12V rating, and 21W output, with the distinction being that the 7440NA includes natural amber glass while the 7440 does not specify a colored envelope.
Because the 7440 and 7440NA share the same physical base and electrical ratings, fitment is mechanically identical between the two, though substituting one for the other may affect the color output depending on the housing design of the vehicle.
The BA15s bayonet base of the 1156NA is a single-contact base, which is distinct from the dual-contact BA15d base used on some other bulb types. Selecting the correct single-contact variant is necessary for proper fitment in the 2014-2016 front turn signal position.
All bulbs listed across both turn signal positions operate on a 12V system and draw 21W, which is consistent with standard incandescent turn signal requirements and relevant to considerations around load-dependent systems such as hyper-flash behavior when non-equivalent replacements are used.