The Mercedes-Benz CL55 AMG front fog light uses a 9006 bulb size, while the rear fog light requires a P21/4W bulb size. The replacement chart covers 2001 to 2006 model production years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz CL55 AMG uses the 9006 bulb for the front fog light position across the 2001-2006 model years.
The 9006 is an ANSI-standard halogen bulb operating at 12V and 55W, fitted with a P22d base and a single filament.
A single-filament design means the 9006 serves one lighting function only, which in this application is front fog illumination.
The rear fog light position across the 2001-2006 model years uses the P21/4W bulb.
The P21/4W is an ECE-standard dual-filament signalling bulb rated at 12V with two wattage outputs: 21W and 4W, fitted with a BAZ15d bayonet base.
The BAZ15d bayonet base on the P21/4W is an offset pin design, which prevents incorrect insertion of a single-filament substitute with a standard BA15s or BA15d base.
The 9006 and P21/4W operate under different international standards, ANSI and ECE respectively, and are not interchangeable with each other due to differences in base type, wattage, and filament configuration.
The P21/4W rear fog bulb draws significantly less wattage than the 9006 front fog bulb, reflecting the different functional demands placed on rear signalling versus forward illumination.