Alfa Romeo Stelvio Headlight Bulb Size

Additional Notes

• The H7 bulb is a single-filament halogen type operating at 12V and 55W, built to ECE standards and approved for use in Europe, the US, Japan, and other worldwide markets. It uses a PX26d base and is present across all six model years covered in the Alfa Romeo Stelvio specifications, serving both high beam and low beam positions in halogen-equipped vehicles from 2018-2023.
• The D3S is a mercury-free HID (high-intensity discharge) xenon bulb rated at 42V and 35W, with a PK32d-5 base that incorporates an integral ignitor. Its design is specific to projector-type housings, which means it is not interchangeable with reflector-style headlight assemblies. It appears in both high beam and low beam positions across all six model years in the Stelvio specifications.
• The H15 is a dual-filament halogen bulb with a PGJ23t-1 base, rated at 12V with two wattage outputs: 55W for the high-intensity filament and 15W for the low-intensity filament. In the Stelvio specifications, it is listed exclusively as a high beam bulb for 2018-2020 model years equipped with halogen capsule headlamps.
• The Alfa Romeo Stelvio with halogen headlights uses different bulb types depending on the model year. The 2018-2020 halogen high beam position calls for an H15, while the 2021-2023 halogen high beam position calls for an H7, making these two groups non-interchangeable despite both being halogen types.
• The low beam position in halogen-equipped Stelvio vehicles uses the H7 across all model years from 2018-2023, regardless of whether the headlamp assembly is described as a halogen capsule type or a halogen lamp type.
• The D3S and H7 are mutually exclusive within any given Stelvio headlight position. The D3S is paired with HID headlight systems, while the H7 is paired with halogen systems. The two bulb types operate on fundamentally different electrical and optical principles and are not substitutable for one another.
• The H15 and H7 share the same voltage rating of 12V but use different bases, PGJ23t-1 and PX26d respectively, making them physically incompatible with each other's sockets. The H15 also carries a dual-filament design, which the single-filament H7 does not.
• The D3S operates at 42V, a voltage level generated internally by the HID ballast system rather than supplied directly by the vehicle's standard 12V electrical circuit. This distinguishes it electrically from both the H7 and H15, which draw power directly from the vehicle's 12V supply.