The Acura TSX high beam headlight uses a 9005 bulb size while the low beam headlight requires a D2S bulb size. The replacement chart covers 2004 through 2010 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 Acura TSX uses the D2S bulb type across all low beam headlight positions for every model year in the specifications, from 2004-2010. The D2S is a high-intensity discharge (HID) xenon bulb rated at 85V and 35W, built to the ECE standard used in Europe and worldwide. It features a P32d-2 base and is designed exclusively for projector-type housings.
Unlike conventional halogen bulbs, the D2S does not contain a self-contained ignition source. It requires a separate external ignitor to generate the high-voltage arc needed to produce light, meaning the surrounding housing assembly is a functional part of the lighting system rather than a passive enclosure.
The high beam headlight position on the Acura TSX (2004-2008) uses the H1 bulb, an ECE-standard single-filament halogen rated at 12V and 55W. Its P14.5s base is a pin-type connector, and while the H1 originates from European standards, it carries approval for use in the United States and Japan as well.
For the 2009-2010 model years, the high beam headlight position shifts from the H1 to the 9005 bulb. The 9005 is an ANSI-standard halogen bulb rated at 12V and 65W, with a P20d base. It operates at a higher wattage than the H1, which corresponds to a higher light output from the high beam circuit in those years.
The H1 and 9005 bulbs are not interchangeable. They differ in base type, wattage, and regulatory standard, meaning a socket designed for one will not physically or electrically accept the other. This distinction is relevant to the TSX high beam position, where the two bulb types apply to different production years.
The D2S bulb, used in the low beam position, operates at 85V, which is substantially higher than the 12V supply voltage of the vehicle's electrical system. A ballast unit steps up the voltage to sustain the xenon arc after the ignitor fires the initial discharge, making both components necessary for the low beam circuit to function.
The D2S designation includes the suffix "S," which indicates compatibility with projector-type optical housings rather than reflector housings. A related bulb, the D2R, carries an internal shield for use in reflector housings and is not a substitute for the D2S in projector applications such as those found in the TSX low beam position.