The Mercedes-Benz GLA250 high beam headlight uses H15 or D3S bulb size, while the low beam headlight requires H7 or D3S bulb size. The replacement chart covers 2015 to 2020 production 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.
ECE standard (Europe & worldwide). Mercury-free HID (xenon) discharge bulb with PK32d-5 base and integral ignitor, for projector-type housings. 42V, 35W.
The H15 bulb is a dual-filament halogen type rated at 12V with a 55W main filament and a 15W secondary filament, using a PGJ23t-1 base. In the Mercedes-Benz GLA250, the higher-wattage filament serves the high beam function, while the lower-wattage filament typically handles daytime running light duties.
The H7 bulb is a single-filament halogen type rated at 12V, 55W, with a PX26d base. It is used exclusively for the low beam position in halogen-equipped GLA250 models across all listed years.
The D3S is a mercury-free high-intensity discharge (HID) xenon bulb rated at 42V, 35W, with a PK32d-5 base. It incorporates an integral ignitor and is designed specifically for projector-type housings. In the GLA250, it serves both high and low beam positions within HID headlamp systems for the 2015-2018 model years.
All three bulb types, H15, H7, and D3S, conform to ECE standards, indicating they are certified for use in Europe and other markets that follow ECE regulations. The H7 additionally carries approval for use in the United States and Japan.
The 2019-2020 GLA250 specifications list only halogen capsule headlamp configurations, with the H15 for high beam and H7 for low beam, while the 2015-2018 model years carried both halogen and HID headlamp variants simultaneously.
The D3S and H7 are not interchangeable. The D3S operates at 42V and requires a projector-type housing along with its built-in ignitor, whereas the H7 is a straightforward 12V halogen bulb. Substituting one for the other is not electrically or physically compatible.
The H15 and H7 also serve distinct positions and are not interchangeable with each other. The H15 uses a PGJ23t-1 base with two filaments, while the H7 uses a PX26d base with a single filament, making the two physically incompatible despite both being 12V halogen types.
GLA250 models equipped with HID headlamps use the D3S for both the high and low beam positions, meaning a single bulb type covers both functions in that headlamp system, unlike the halogen configuration which requires separate H15 and H7 bulbs for each position.