Toyota Avalon Turn Signal Bulb Size

Additional Notes

• The Toyota Avalon front turn signal uses the 7444NA bulb across the 2013-2019 model years. This is a dual-filament T20 wedge bulb rated at 12V with a 21W high filament and a 5W low filament, featuring natural amber glass that produces the required amber signal color without a separate amber lens.
• The "NA" suffix found on bulb designations such as 7444NA, 3457NA, 3157NA, 1034NA, and 1157NA indicates natural amber glass. This coloring is built into the glass envelope itself rather than relying on an amber-tinted housing or lens to produce the legally required amber turn signal output.
• The 7440NA is the most consistently used rear turn signal bulb in the Avalon, covering the 2003-2012 model years. It is a single-filament T20 wedge bulb rated at 12V and 21W with natural amber glass, making it functionally identical to the 7440 except for the amber glass coating.
• The 7440 and 7440NA share the same T20 wedge base, voltage rating, and 21W wattage. The Avalon rear turn signal specifications list the 7440 (without the NA suffix) for the 1998-2002 model years, indicating those vehicles relied on an amber lens or housing rather than the bulb glass itself for color output.
• The front turn signal for the 2005-2008 and 2011-2012 Toyota Avalon uses the 3457NA, a dual-filament T25 wedge bulb rated at 12V with filaments at 27W and 7W. The higher wattage of this bulb compared to the 7444NA reflects a different optical and electrical design in the front lamp assemblies of those generations.
• The 1034NA, used in the Avalon front turn signal for the 2001 and 2004 model years, is classified as a variant of the 1157NA. Both use a BAY15d dual-contact bayonet base and operate at 12V with 21W and 5W filaments. Despite their functional similarity, the two designations are not universally interchangeable, as minor dimensional differences in the base or envelope can affect fitment in specific housings.
• The 1156 bulb, used in both the front and rear turn signals of the 1995-1997 Avalon, uses a BA15s single-contact bayonet base. This base type is mechanically distinct from the BAY15d dual-contact base found on bulbs such as the 1157NA and 1034NA, meaning these bayonet-type bulbs are not interchangeable with wedge-base types regardless of wattage similarity.
• The 3357NA, specified for the Avalon front turn signal in 2009-2010, is a single-filament T25 wedge bulb rated at 12V and 27W. Although it shares the T25 wedge base with the dual-filament 3457NA used in adjacent model years, the single-filament construction makes it electrically incompatible as a direct substitute in sockets wired for dual-filament operation.
• The rear turn signal for the 2013-2019 Avalon uses the 921, a T15 wedge bulb rated at 12V and 16W. This bulb carries no NA suffix, which distinguishes it from the natural amber wedge bulbs used in the front position during the same years, suggesting the rear lamp assemblies of that generation use an amber-colored lens or reflector housing to achieve the required signal color.
• Wedge-base bulbs such as the T20 and T25 types are retained in their sockets by the tension of the base contacts alone, without a locking bayonet mechanism. While T20 and T25 wedge bulbs may appear physically similar, their base widths differ, and substituting one for the other risks a loose fit or failure to make proper electrical contact in the socket.