The Mercedes-Benz CLK63 AMG front fog light uses an H7 bulb size while the rear fog light requires a P21/4W bulb size. The replacement chart covers 2007 to 2008 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 CLK63 AMG uses the H7 bulb for the front fog light position across the 2007-2008 model years.
The H7 is a single-filament halogen bulb operating at 12V and 55W, fitted with a PX26d base, and is certified under ECE standards with approval also extended to the US and Japan.
The PX26d base is a two-pin connector with a locking collar, a design that prevents rotation and ensures a fixed orientation in the housing.
The rear fog light position on the CLK63 AMG uses the P21/4W bulb across the 2007-2008 model years.
The P21/4W is a dual-filament signalling bulb rated at 12V with two wattage outputs of 21W and 4W, mounted on a BAZ15d bayonet base.
The BAZ15d base is an offset single-contact bayonet fitting, where the two pins are positioned at different heights to prevent incorrect installation of the bulb.
The dual-filament design of the P21/4W allows it to serve two distinct lighting functions within a single bulb unit, with the 21W filament typically handling the primary signal function and the 4W filament serving as a secondary or position light.
Both the H7 and P21/4W are governed by ECE regulations, meaning they conform to internationally recognized photometric and safety standards used across European and worldwide markets.
The H7 and P21/4W use physically distinct base types, PX26d and BAZ15d respectively, making the two bulbs non-interchangeable with each other or with bulbs from other base families.