The Mercedes-Benz CLS63 AMG front fog light utilizes H7 and H11 bulb sizes, while the rear fog light requires a 921 size bulb. The replacement chart covers 2007 to 2011 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz CLS63 AMG front fog light uses the H7 bulb for 2007 and 2009-2011, while the 2008 model year uses the H11 bulb instead.
The H7 is a single-filament halogen bulb operating at 12V and 55W, built to ECE standards with a PX26d base, and carries approval for use in the US and Japan in addition to European and worldwide markets.
The H11 is also a single-filament halogen bulb rated at 12V and 55W under ECE standards, but it uses a PGJ19-2 base, which is physically incompatible with the PX26d socket required by the H7.
Because the H7 and H11 use different base types, the two bulbs are not interchangeable, making the 2008 front fog light socket incompatible with bulbs specified for the 2007 and 2009-2011 model years.
The rear fog light on the CLS63 AMG uses the 921 bulb across all listed model years, spanning 2007-2011.
The 921 is a wedge-type bulb in the T15 form factor, rated at 12V and 16W, and follows ANSI standards applicable to the US and Canada.
At 16W, the 921 rear fog bulb draws significantly less power than the 55W halogen bulbs used in the front fog positions, reflecting the different functional demands placed on rear fog lighting.
The wedge base of the 921 bulb differs structurally from the pin-type bases of the H7 and H11, meaning none of the front fog bulb types are compatible with the rear fog light socket.