The Lexus GS450h uses a D4S bulb size for low beam headlights and either D4S or 9005 bulb size for high beam headlights. The replacement chart covers vehicle production years spanning 2007 to 2015 with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The D4S is the most frequently specified bulb type across the Lexus GS450h headlight data, appearing in both high beam and low beam positions for the 2013-2015 model years, and exclusively in the low beam position for the 2007-2011 model years.
The D4S operates as a mercury-free HID (xenon) gas discharge bulb rated at 42V and 35W, conforming to ECE standards used in Europe and worldwide markets. Its P32d-5 base is designed specifically for projector-type housings.
The 9005 is a single-filament halogen bulb rated at 12V and 65W, conforming to ANSI standards applicable to the US and Canadian markets. It uses a P20d base, which is physically and electrically incompatible with the P32d-5 base of the D4S.
For the Lexus GS450h, the 2007-2011 model years use a split-type headlight configuration, with the 9005 halogen bulb in the high beam position and the D4S HID bulb in the low beam position.
The 2013-2015 model years specify the D4S for both high beam and low beam positions, with the notation "With HID Headlamps" indicating this fitment is conditional on the vehicle being equipped with HID headlamps.
The base types of the D4S (P32d-5) and the 9005 (P20d) are not interchangeable. Substituting one for the other is not possible without modification to the housing or wiring.
The voltage difference between the D4S (42V) and the 9005 (12V) reflects fundamentally different operating systems. HID systems require a ballast to generate the high-voltage arc needed to ignite the xenon gas, while the 9005 operates directly on a standard 12V automotive circuit.
The wattage difference between the D4S (35W) and the 9005 (65W) is notable given that the HID bulb produces significantly greater luminous output despite drawing less power, a characteristic inherent to gas discharge technology.