The Audi 90 uses 9003 and 9004 bulb sizes for both high beam and low beam headlight applications. The replacement chart covers vehicle production spanning 1988 to 1995 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 Audi 90 uses two distinct bulb types across its model years: the 9003 and the 9004, both of which are ANSI-standard halogen bulbs approved for use in the United States and Canada.
Both the 9003 and 9004 are dual-filament bulbs, meaning a single bulb serves both the high beam and low beam functions. This is reflected in the specifications, where the same bulb size is listed for both sub-parts across all model years.
The 9003 bulb operates at 12 volts with a wattage rating of 60W on the high beam filament and 55W on the low beam filament. It uses a P43t base.
The 9004 bulb also operates at 12 volts but carries a higher wattage on the high beam filament at 65W, while the low beam filament draws 45W. It uses a P29t base.
The Audi 90 for model years 1993-1995 requires the 9003 bulb, while the 1988-1991 model years require the 9004 bulb. The P43t and P29t bases are not interchangeable, so the two bulb types cannot be substituted for one another.
The difference in base type between the 9003 (P43t) and 9004 (P29t) is a physical fitment distinction. A bulb with the wrong base will not seat correctly in the headlight housing.