The Lexus ES250 high beam and low beam headlight bulbs both utilize a 9004 bulb size. The replacement chart covers vehicle production spanning 1990 to 1991.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 9004 is a dual-filament halogen bulb, meaning a single unit contains two separate filaments to serve two distinct lighting functions. It operates on a 12-volt electrical system and draws 65 watts on the high beam filament and 45 watts on the low beam filament.
The 9004 bulb uses a P29t base, which is a three-pronged plastic connector specific to this bulb family. This base type is not interchangeable with other common automotive base types such as H4 or 9007, even though those bulbs serve a similar dual-filament purpose.
The 9004 specification is governed by ANSI standards and is approved for use in the United States and Canada. This regional standardization means the bulb conforms to specific photometric and dimensional requirements set for North American markets.
On the Lexus ES250, the 9004 bulb serves both the high beam and low beam headlight positions for the 1990-1991 model years. A single bulb type fulfilling both functions is a characteristic of systems that use a dual-filament design rather than separate bulbs for each beam.
Because the same 9004 bulb is specified for both the high beam and low beam housings, the two filaments within the bulb are activated independently depending on which beam is selected by the driver. The higher-wattage filament at 65 watts corresponds to the high beam, while the 45-watt filament serves the low beam.
The 9004 and 9007 bulbs are physically similar in appearance but are not interchangeable. The P29t base on the 9004 has a different key orientation than the 9007, which prevents incorrect installation in most housings designed for one or the other.