Lexus RC300 Courtesy Bulb Size

Additional Notes

• The 194 and 168 bulbs are both ANSI-standardized miniature wedge types sharing the T10 form factor and a 12-volt operating voltage, making them physically interchangeable in many sockets.
• Despite their shared T10 form factor, the 194 and 168 bulbs carry different wattage ratings, at 3.78W and 4.9W respectively, which means they are not electrically identical substitutes.
• The Lexus RC300 uses the 194 bulb for courtesy lighting in the 2021-2022 model years, while the 2016 model year uses the higher-wattage 168 bulb instead.
• The T10 wedge base is a common automotive miniature bulb format in which the glass envelope and filament assembly are held directly by two wire leads that form the wedge-shaped base, requiring no separate metal shell or bayonet pins.
• Both the 194 and 168 designations follow ANSI standards applicable to the US and Canadian markets, indicating that bulb performance characteristics such as voltage, wattage, and light output conform to defined industry specifications within those regions.
• The wattage difference between the two bulb types means that substituting a 168 in place of a 194 in a 2021-2022 RC300 would result in higher power draw than the vehicle's courtesy lighting circuit was rated for in those years.