Acura RL Turn Signal Bulb Size

Additional Notes

• The 1034NA bulb is a dual-filament type with a BAY15d bayonet base, rated at 12V and 21/5W, and features natural amber glass. It is a variant of the 1157 bulb family, meaning it shares the same base type but differs in wattage output on the high-filament circuit.
• The 1157NA bulb also uses a BAY15d bayonet base and natural amber glass, rated at 12V and 21W/5W. Although the 1034NA and 1157NA share the same base, their differing wattage ratings mean they are not directly interchangeable without accounting for circuit expectations.
• The 7440NA is a single-filament T20 wedge bulb with natural amber glass, rated at 12V and 21W. Its wedge base design differs fundamentally from the BAY15d bayonet base used by the 1034NA and 1157NA, making cross-substitution between these types physically incompatible.
• The 3497 is a single-filament bulb with a BA15s bayonet base, rated at 12V and 21W. It is a variant of the 1156 bulb. The BA15s base has a single contact pin, distinguishing it from the dual-pin BAY15d base found on the 1034NA and 1157NA.
• The Acura RL front turn signal used the 3497 bulb for the 1996-1998 model years, then transitioned to the 1034NA for 1999-2001, before shifting to the 1157NA for 2002-2004. This reflects three distinct base and filament configurations across the front position over that span.
• For the 2008 Acura RL, the front turn signal bulb specification splits by trim configuration: the 1034NA applies to vehicles with Adaptive Lighting, while the 7440NA applies to those without. These two bulbs use different base types, so fitment is determined by the vehicle's lighting system variant.
• The same adaptive lighting split existed in the 2007 Acura RL, where the front turn signal used the 1157NA with Adaptive Lighting and the 7440NA without. The 1157NA and 1034NA are both BAY15d dual-filament types, while the 7440NA is a single-filament wedge, reinforcing that the two trim variants require physically different bulbs.
• The rear turn signal of the Acura RL used the 7440 (without natural amber glass) for the 1996-2001 model years, then the 12496 for 2003-2004, before returning to the 7440NA designation for 2005-2012. The 7440 and 7440NA share the same T20 wedge base and 12V/21W rating, with the NA suffix indicating the natural amber glass coating.
• The 12496 rear turn signal bulb, used on the 2003-2004 Acura RL, is identified as a Philips/Osram part number rather than an ANSI standard designation. It is rated at 12V and classified as a specialty halogen application, which distinguishes it from the standardized ANSI bulbs used in surrounding model years.
• Across the full specification range, the front turn signal position of the Acura RL used four distinct bulb types: the 3497, 1034NA, 1157NA, and 7440NA. Each involves a different base or filament configuration, and none of these four types are directly interchangeable with one another without a corresponding socket match.