The Lexus RX300 front turn signal uses a 7440 bulb size, while rear turn signals accommodate PY21W, 12496, or 7440 bulb sizes across different positions. The replacement chart covers vehicle production spanning 1999 to 2003 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 Lexus RX300 front turn signal uses the 7440 bulb across all model years from 1999-2003, making it the most consistently specified bulb in these fitment data.
The 7440 is an ANSI-standard single-filament wedge bulb in the T20 form factor, rated at 12V and 21W, and is the predominant standard in the United States and Canada.
The PY21W is an ECE-standard single-filament amber bulb operating at 12V and 21W, but it uses a BAU15s bayonet base rather than the wedge base found on the 7440, making the two bulbs physically non-interchangeable despite sharing the same wattage.
The rear turn signal of the RX300 does not follow a single consistent bulb type across its production run, with three distinct bulb sizes specified across the 1999-2003 model years.
The 1999-2000 rear turn signal uses the 7440, the same wedge-base bulb as the front position, while the 2001 and 2003 model years specify the PY21W with its bayonet base.
The 2002 rear turn signal is specified with bulb number 12496, a Philips/Osram part number designating a halogen bulb for specialty applications, rated at 12V.
Because the 7440 and PY21W use fundamentally different base types, a wedge socket and a BAU15s bayonet socket respectively, substituting one for the other in any position is not physically possible without socket modification.
The 12496 is identified by a manufacturer part number rather than an ANSI or ECE standard designation, which places it outside the two primary international bulb classification systems represented elsewhere in these specifications.