The Mercedes-Benz CLA45 AMG uses H15 and D3S bulb sizes for high beam headlights, along with H7 and D3S bulb sizes for low beam headlights. A replacement chart covering 2014 to 2019 model years contains vehicle production years and 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 CLA45 AMG, the higher-wattage filament serves the high beam function, while the lower-wattage filament typically handles daytime running light duty.
The H7 bulb is a single-filament halogen type rated at 12V, 55W, with a PX26d base. It is dedicated exclusively to low beam output, as its single-filament construction does not support a secondary lighting function.
The D3S is a mercury-free high-intensity discharge xenon bulb rated at 42V, 35W, with a PK32d-5 base. It incorporates an integral ignitor and is designed specifically for projector-type headlamp housings. The higher operating voltage relative to halogen types requires a dedicated ballast within the headlamp assembly.
All three bulb types, H15, H7, and D3S, conform to ECE standards, indicating they are certified for use in Europe and other markets that recognize ECE regulations. The H7 additionally carries approval for use in the United States and Japan.
For the 2017-2019 model years, the CLA45 AMG with halogen capsule headlamps uses the H15 for high beam and the H7 for low beam. No HID option is listed for those years.
For the 2014-2016 model years, two distinct headlamp configurations are listed. Vehicles equipped with halogen capsule headlamps use the H15 for high beam and the H7 for low beam, while vehicles equipped with HID headlamps use the D3S for both high and low beam positions.
The D3S and H7 are not interchangeable despite both being used in the low beam position across different headlamp configurations. The D3S requires a projector housing and an HID ballast, whereas the H7 operates in a standard halogen reflector or projector housing at 12V without additional ignition components.
The H15 used in the high beam position of halogen-equipped vehicles is also not interchangeable with the D3S used in HID-equipped vehicles for the same function, as the two bulbs differ in base type, operating voltage, and housing compatibility.