The Mercedes-Benz C43 AMG front fog light requires an H1 bulb size while the rear fog light uses a P21/4W bulb size. The replacement chart covers vehicle production years spanning 1998 to 2000.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz C43 AMG uses the H1 bulb for the front fog light position across the 1998-2000 model years.
The H1 is a single-filament halogen bulb operating at 12V and 55W, fitted with a P14.5s base, and manufactured to the ECE standard used in Europe and worldwide.
Although the H1 originates from the ECE regulatory framework, it also carries approval for use in the United States and Japan, making it one of the more broadly accepted halogen types across major automotive markets.
The rear fog light position on the C43 AMG uses the P21/4W bulb across the same 1998-2000 model years.
The P21/4W is a dual-filament signalling bulb rated at 12V with two wattage outputs: 21W and 4W. It uses a BAZ15d bayonet base, which is an offset-pin fitting designed to prevent incorrect installation.
The BAZ15d base on the P21/4W is mechanically distinct from single-filament bayonet bases, meaning it is not interchangeable with bulbs such as the P21W, which uses a BA15s base.
The H1 uses a P14.5s base, a single-pin connector that is specific to the H1 type. This base is not shared with other common halogen types such as the H4 or H7, which use different base configurations entirely.
Both the H1 and P21/4W conform to ECE regulations, indicating that the fog light system on the C43 AMG was designed around European lighting standards.