Lexus IS350 Courtesy Bulb Size

The Lexus IS350 courtesy light uses 168 and 194 bulb sizes for the interior lighting components. Available data covers the specific time period from 2006 through 2024 for the listed vehicle.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	US Type	EU Type	Shop
2021-2024	168	W5W	Check Price
2016-2019	168	W5W	Check Price
2006-2009	194	W5W	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 4.9W.	168	Check Price
ECE standard (Europe & worldwide). Single-filament signalling bulb with W2.1x9.5d wedge base. 12V, 5W.	W5W	Check Price
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 3.78W.	194	Check Price

Other Locations

Additional Notes

The 168 and 194 are both ANSI-standardized miniature wedge bulbs sharing the T10 form factor and a 12-volt operating voltage, making them physically interchangeable in terms of socket fit.
Despite the shared T10 socket, the 168 and 194 differ in wattage: the 168 draws 4.9 watts while the 194 draws 3.78 watts, meaning they are not electrically identical and should not be treated as direct substitutes.
The Lexus IS350 uses the 168 bulb for courtesy lighting across the 2016-2019 and 2021-2024 model years.
The 2006-2009 model years of the Lexus IS350 use the 194 bulb for courtesy lighting, which carries a lower wattage rating than the 168 used in later model years.
Because the 168 and 194 share the same T10 wedge base, a physically incorrect substitution between the two is possible without obvious resistance at installation, making wattage verification an important step before fitment.
Both bulb types conform to ANSI standards applicable in the United States and Canada, indicating standardized electrical and physical tolerances across manufacturers producing these part numbers.