The Lexus RX330 dome light requires a bulb size of 578 for the interior lighting system. Data for the specific component covers the range from 2004 to 2006.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Lexus RX330 uses two festoon bulb types across its dome light positions for the 2004-2006 model years: the 578 and the DE3175.
Festoon bulbs are cylindrical lamps that make electrical contact through metal caps at each end rather than through a base socket, which is the defining characteristic of the end-cap contact design shared by both the 578 and DE3175.
The 578 bulb is specified for the general dome light position across all three model years and operates at 12V with a 12W power rating.
The DE3175 is specified for both the front and rear dome light positions across the 2004-2006 model years and operates at 12V.
Both bulb types conform to ANSI standards applicable in the United States and Canada.
The 578 and DE3175 are physically incompatible with each other due to differing lengths: the 578 measures 41mm while the DE3175 measures 31mm. Substituting one for the other would result in an improper fit within the lamp housing.
The DE3175 is the more frequently specified bulb in the RX330 dome light system, covering two distinct sub-positions compared to the single position served by the 578.