Mercedes-Benz S320 Headlight Bulb Size

Additional Notes

• The H1 bulb is a single-filament halogen type operating at 12V and 55W, built to the ECE standard and approved for use in the US and Japan. It fits a P14.5s base and serves exclusively as the high beam bulb in the Mercedes-Benz S320 for model years 1995-1999.
• The 9003 bulb is a dual-filament halogen type operating at 12V with a 60W high beam filament and a 55W low beam filament. Built to the ANSI standard, it uses a P43t base and handled both high and low beam functions in the 1994 S320 within a single unit.
• Because the 9003 bulb carries both filaments in one unit, the 1994 S320 used a single bulb type for both beam functions. From 1995 onward, the S320 shifted to separate bulb types for each function, making the two configurations incompatible with each other.
• The H7 bulb is a single-filament halogen type operating at 12V and 55W, built to the ECE standard and approved in the US and Japan. It uses a PX26d base and serves as the low beam bulb in the S320 for model years 1995-1999, though 1997-1999 vehicles with HID headlamps use a different bulb in that position.
• The D2R is an HID xenon discharge bulb rated at 85V and 35W, using a P32d-3 base. It is designed specifically for reflector-type housings and requires an external ignitor to operate, distinguishing it from all halogen types in these specifications.
• For model years 1997-1999, the Mercedes-Benz S320 low beam position accepted either an H7 or a D2R bulb depending on the headlamp system installed at the factory. The two types are not interchangeable, as they operate on fundamentally different electrical and optical principles.
• The H1 and H7 bulbs share the same voltage and wattage ratings but use different base types, P14.5s and PX26d respectively, meaning one cannot substitute for the other despite their similar electrical characteristics.