The Lexus RX350 side marker utilizes a 168 bulb size for the lighting components located on the exterior of the vehicle. Data for the specific lighting requirements covers the period from 2021 through 2021.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Lexus RX350 front side marker uses two distinct bulb sizes across its model years: the 12961 and the 168, both of which belong to the T10 miniature wedge family and share the same physical form factor.
The 168 is defined by the ANSI standard applicable in the US and Canada, rated at 12V and 4.9W, and serves as the front side marker bulb on the RX350 for 2007-2012 and 2016-2018.
The 12961 is a Philips part number designation for a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12V and 5W, and is specified for the RX350 front side marker in 2015, 2021, and 2022.
Although the 168 and 12961 are both T10 wedge bulbs with nearly identical wattage ratings, the 12961 carries a manufacturer-specific part number rather than an ANSI designation, which can affect direct interchangeability depending on socket tolerances.
The 2019 Lexus RX350 front side marker uses the 12961, while the immediately surrounding model years of 2016-2018 use the 168, indicating a bulb specification change at the generation boundary.
The rear side marker on the RX350 uses the 194 bulb for 2007-2009, which is an ANSI-standard T10 miniature wedge rated at 12V and 3.78W, making it the lowest-wattage bulb among the three types listed in these specifications.
The rear side marker transitions from the 194 to the 168 starting with the 2010 model year, continuing through 2015, representing a wattage increase from 3.78W to 4.9W at that point in the vehicle's production history.
The 194 and 168 bulbs share the same T10 wedge base type, but their differing wattage ratings mean they are not electrically equivalent, and substituting one for the other may affect light output or circuit behavior.
The W2.1x9.5d base designation on the 12961 refers to a wedge base with a 2.1mm wire width and a 9.5mm insertion depth, which is the standard geometry for T10 wedge bulbs and is consistent with the socket type used across all three bulb sizes in these specifications.
No rear side marker specification is listed for the RX350 for 2016 onward, while the front side marker specification continues through 2022, reflecting a difference in how the two positions are documented across the vehicle's generation changes.