Acura RDX Turn Signal Bulb Size

Additional Notes

• The 7443NA is a dual-filament T20 wedge bulb rated at 12V with a 21W main filament and a 5W secondary filament. Its natural amber glass produces the required amber signal color without relying on a colored lens or housing.
• The 1034NA and 1157NA are both dual-filament bulbs sharing the BAY15d bayonet base and the same 12V, 21W/5W electrical rating. The 1034NA is a variant of the 1157NA, and both carry natural amber glass for turn signal applications.
• The 7440 is a single-filament T20 wedge bulb rated at 12V and 21W. Although it shares the T20 wedge form with the 7443NA, the 7443NA carries a second filament, making the two types non-interchangeable despite their physical similarity.
• The PY21W uses a BAU15s bayonet base, which has offset pins at an unequal angular spacing. This base is distinct from the BAY15d base used by the 1034NA and 1157NA, and the two base types are not physically interchangeable.
• The Acura RDX front turn signal used the 1034NA from 2007-2010 and again in 2012-2015 with the 7443NA, while the 2008 model year used the 1157NA, making it the sole year in the front turn signal data to specify that bulb.
• The rear turn signal of the Acura RDX used the 7440 from 2007-2018, then transitioned to the PY21W for 2019-2022. The PY21W follows the ECE standard used in European and worldwide markets, whereas the 7440 follows the ANSI standard used in the US and Canada.
• The 7443NA and 1034NA used in the front turn signal positions are both dual-filament bulbs, which allows a single bulb to serve both a running light function and a turn signal function simultaneously within the same housing.
• The PY21W and 7440 are both single-filament 21W bulbs, but they use different base types and different regulatory standards, meaning one cannot substitute for the other despite sharing the same wattage.