Mercedes-Benz ML320 Headlight Bulb Size

Additional Notes

• The H7 bulb is the most widely used type across the Mercedes-Benz ML320 headlight specifications, appearing in both high beam and low beam positions across multiple model years. It is a single-filament halogen bulb rated at 12V and 55W, fitted with a PX26d base, and meets ECE standards with approval in the US and Japan.
• The H1 bulb serves the high beam position on the Mercedes-Benz ML320 for the 1998-2001 model years. Like the H7, it is a single-filament halogen bulb rated at 12V and 55W under ECE standards, but it uses a P14.5s base, which is physically incompatible with the PX26d base of the H7. The two types are not interchangeable despite sharing the same voltage and wattage ratings.
• From 2002 onward, the high beam position transitioned from H1 to H7. This base type change means that housings designed for one are not compatible with the other, as the P14.5s and PX26d bases have distinct pin configurations and locking mechanisms.
• The low beam position on the ML320 accommodates either halogen or HID (high-intensity discharge) technology depending on the headlamp system installed on the vehicle. The halogen variant uses an H7 bulb across all listed years, while the HID variant uses D-series xenon bulbs that vary by year.
• Three distinct HID bulb types appear in the low beam specifications: D2R for 2000-2001, D2S for 2002-2003 and 2007, and D1S for 2008-2009. The D2R uses a P32d-3 base intended for reflector-type housings, while the D2S uses a P32d-2 base for projector-type housings. These two types are not interchangeable despite sharing the same 85V, 35W electrical rating, as their optical and base configurations differ.
• The D1S, used in 2008-2009 HID low beam applications, differs from the D2S in that it incorporates an integral ignitor within the bulb itself, using a PK32d-2 base. The D2S and D2R require an external ignitor in the vehicle's ballast circuit. This distinction makes D1S and D2S bulbs electrically and physically incompatible with each other.
• All three HID types (D1S, D2S, D2R) operate at 85V and 35W, which contrasts sharply with the 12V, 55W rating of the halogen H7 and H1 types. HID systems require a ballast to generate and regulate the high voltage needed for xenon arc discharge, meaning the two headlamp technologies rely on fundamentally different electrical architectures.
• The 1998 and 1999 low beam positions list only H7 without any HID variant, indicating that those model years carried halogen-only low beam configurations according to the specifications. The high beam for those same years used H1, resulting in two different halogen base types within the same headlamp assembly.