The Mercedes-Benz SL550 headlight bulb sizes include D1S, H7 for high beam and D1S, D2S for low beam applications. The replacement chart covers 2007 to 2016 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 D1S bulb is an HID (xenon) discharge type operating at 85V and 35W, distinguished by its PK32d-2 base and a factory-integrated ignitor. This self-contained ignitor design sets it apart from other HID types that rely on a separate external component.
The D2S bulb shares the same 85V, 35W operating profile as the D1S but uses a P32d-2 base and requires an external ignitor rather than an integrated one. Both types are designed exclusively for projector-type housings.
Although the D1S and D2S share identical wattage and voltage ratings, their base types and ignitor configurations are not the same, meaning the two bulbs are not interchangeable despite their similar electrical characteristics.
The H7 is a single-filament halogen bulb rated at 12V and 55W, fitted with a PX26d base. Unlike the HID types used elsewhere in these specifications, it operates on standard low-voltage automotive power without requiring a ballast or ignitor.
The Mercedes-Benz SL550 high beam headlight shifted from the H7 halogen type, used in 2007-2012, to the D1S HID type for 2013-2016, indicating a change in headlight system design between those model year groups.
The low beam headlight on the 2007-2008 SL550 uses the D2S bulb, while 2009-2016 models use the D1S. Both are HID projector bulbs, but the base and ignitor configuration differ between them, making them non-interchangeable.
All three bulb types listed, the D1S, D2S, and H7, conform to ECE standards applicable in Europe and worldwide. The H7 additionally carries approval for use in the United States and Japan.
The 2012 SL550 uses a split headlight bulb arrangement: the high beam uses the H7 halogen type while the low beam uses the D1S HID type, meaning the two headlight functions on that model year rely on fundamentally different lamp technologies and power requirements.