The Mercedes-Benz CLK500 front fog light uses H7 and 9006 bulb sizes, while the rear fog light requires a P21/4W bulb size. The replacement chart covers 2003 to 2006 model 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 CLK500 front fog light uses two different bulb types across its model years, with the 9006 fitted in 2003-2005 and the H7 fitted in 2006.
The H7 is an ECE-standard single-filament halogen bulb rated at 12V and 55W, mounted on a PX26d base. It holds approval for use in the US and Japan in addition to European and worldwide markets.
The 9006 is an ANSI-standard single-filament halogen bulb also rated at 12V and 55W, but it uses a P22d base rather than the PX26d base found on the H7.
Although the H7 and 9006 share the same voltage and wattage ratings, their bases are physically different and the two types are not interchangeable with each other.
The rear fog light on the CLK500 uses the P21/4W bulb across all four model years covered, from 2003 through 2006.
The P21/4W is an ECE-standard dual-filament signalling bulb rated at 12V with a 21W primary filament and a 4W secondary filament, mounted on a BAZ15d bayonet base.
The BAZ15d bayonet base of the P21/4W is an offset pin design, a feature that prevents incorrect installation by ensuring the bulb seats in only one orientation.
The front fog light specification change from 9006 to H7 between the 2005 and 2006 model years means parts sourced for earlier CLK500 front fog lights are not compatible with the 2006 model.