The Lexus IS250 high beam headlight uses a 9005 bulb size, while low beam headlights require H11 or D4S bulb sizes. The replacement chart covers 2006 through 2009 model years 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 IS250 (2006-2009) uses the 9005 bulb for the high beam headlight across all four model years covered in these specifications. The 9005 is an ANSI-standard single-filament halogen bulb rated at 12V and 65W, fitted with a P20d base, and is the prevailing standard in the United States and Canada.
The low beam headlight position on the IS250 (2006-2009) accommodates two distinct bulb types depending on the headlamp system installed at the factory. Vehicles equipped with halogen capsule headlamps use the H11, while those fitted with HID headlamps use the D4S.
The H11 is a single-filament halogen bulb operating at 12V and 55W. It follows the ECE standard used across Europe and internationally, though it also carries approval for use in the United States. Its base type is PGJ19-2, which is not interchangeable with the P20d base of the 9005 despite both being single-filament halogen bulbs.
The D4S is a mercury-free high-intensity discharge bulb, commonly referred to as a xenon bulb, rated at 42V and 35W. Its significantly higher operating voltage relative to the halogen alternatives reflects the nature of HID arc discharge technology, which requires a high-voltage ignition pulse and a dedicated ballast to sustain the arc.
The D4S carries a P32d-5 base and is specified exclusively for projector-type housings. This housing requirement is a fitment constraint, as the optical design of a projector housing is necessary to control and focus the light output produced by an HID source.
The base types across the three bulbs in these specifications are all distinct: P20d for the 9005, PGJ19-2 for the H11, and P32d-5 for the D4S. These differences in base configuration mean none of the three bulbs are physically interchangeable with one another.
The 9005 and H11 both operate on a standard 12V automotive circuit, whereas the D4S operates at 42V and requires a ballast unit to function. Substituting a halogen bulb into an HID housing, or vice versa, is not supported by these specifications and would involve incompatible electrical and optical systems.
The H11 and D4S low beam options apply uniformly across all four model years (2006-2009) in these specifications, indicating that the halogen and HID headlamp configurations were both available throughout the entire production span covered here.