Acura RLX front turn signal bulbs use 1157NA or 1034NA size, while rear turn signal bulbs use 7440 size. The replacement chart covers 2014 through 2018 vehicle production 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 Acura RLX front turn signal uses the 1157NA bulb across the 2014-2016 and 2018 model years. This is a dual-filament bulb with a BAY15d bayonet base, natural amber glass, rated at 12V with a 21W/5W output.
The 2017 Acura RLX front turn signal takes a 1034NA bulb rather than the 1157NA used in surrounding model years. The 1034NA is a variant of the 1157 and shares the same BAY15d bayonet base, dual-filament design, natural amber glass, and 12V/21W/5W rating.
Because the 1034NA is a variant of the 1157, the two types share the same BAY15d bayonet base and electrical ratings. However, they are listed as distinct part numbers in the specifications, and substitution between them should be treated with caution.
The BAY15d bayonet base found on both the 1157NA and 1034NA features offset pins, which prevents incorrect insertion. This base type is common in dual-filament automotive applications where separate circuits control stop and tail or turn and parking functions.
The natural amber glass of the 1157NA and 1034NA produces an amber output directly from the bulb itself, without relying on a colored lens to filter a clear light source.
The rear turn signal on the Acura RLX uses the 7440 bulb across all listed model years, 2014-2018. Unlike the front position, the rear specification shows no variation across this range.
The 7440 is a single-filament T20 wedge bulb rated at 12V and 21W. Its single-filament construction means it serves one function only, in contrast to the dual-filament bulbs used at the front.
The T20 wedge base of the 7440 is held in place by friction within the socket rather than by a locking bayonet mechanism. The 7440 and its close relative the 7443 share the same T20 form factor but differ in filament count, making them physically similar yet not interchangeable in all applications.