The Volvo 240 uses the 9004 bulb for both high beam and low beam headlights across the 1990-1993 model years.
The 9004 is a dual-filament halogen bulb, meaning a single bulb contains two separate filaments to serve both high and low beam functions within one housing.
Because the 9004 handles both beam functions in the Volvo 240, replacing either the high or low beam requires the same bulb part number in all four listed model years.
The 9004 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 uses a P29t base, which is a specific connector type that is not interchangeable with other common halogen base types such as H4 or 9007 without modification.
The 9004 is an ANSI-standardized bulb approved for use in the United States and Canada, meaning it conforms to a defined set of photometric and dimensional requirements for road use in those markets.