Mercedes-Benz GLC43 AMG high beam and low beam headlight bulbs both use H7 size. The replacement chart covers 2017 to 2020 model years with bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The H7 bulb is the sole bulb type specified across all high beam and low beam headlight positions for the Mercedes-Benz GLC43 AMG across the 2017-2020 model years.
The H7 is a single-filament halogen bulb operating at 55 watts with a PX26d base, a two-pin connector design that is not interchangeable with other common bases such as the H4 or H11.
For the 2019-2020 model years, both the high beam and low beam positions carry a "With Halogen Capsule Headlamps" qualifier, indicating that the H7 fitment applies specifically to vehicles equipped with that headlamp configuration rather than to all trim or equipment variants.
The 2017-2018 model years list H7 for both beam positions without a headlamp-type qualifier, suggesting the specification applied without a conditional equipment distinction during those years.
Because both the high beam and low beam positions share the H7 bulb type, the same physical bulb serves both functions, though the two positions remain separate housings and are not interchangeable in their mounting locations.
The PX26d base of the H7 uses a locking tab retention system, meaning installation requires alignment of the tab with the corresponding slot in the headlamp housing rather than a simple twist-lock motion.