The Mercedes-Benz ML63 AMG front fog light uses H11 or H7 bulb sizes, while the rear fog light requires 921 or P21W bulb sizes. The replacement chart covers 2007 through 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 ML63 AMG front fog light specification changed from H7 to H11 between the 2009 and 2010 model years, meaning the two generations of this model within the 2007-2011 range require different front fog light bulbs.
The H7 bulb, used in the front fog lights of the 2007-2009 ML63 AMG, is a single-filament halogen type operating at 12V and 55W, fitted with a PX26d base and recognized under ECE standards across Europe, the US, and Japan.
The H11 bulb, used in the front fog lights of the 2010-2011 ML63 AMG, is also a single-filament halogen type at 12V and 55W, but it uses a PGJ19-2 base rather than the PX26d base of the H7, making the two bulbs physically incompatible despite sharing the same wattage and voltage rating.
Although the H7 and H11 share identical electrical ratings of 12V and 55W, their base types differ, and one cannot be substituted for the other without a fitting adapter or socket modification.
The rear fog light specification for the ML63 AMG also changed within the 2007-2011 range, with the P21W used on 2007-2008 models giving way to the 921 on 2009-2011 models.
The P21W, used in the rear fog lights of the 2007-2008 ML63 AMG, is an ECE-standard single-filament signalling bulb with a BA15s bayonet base, rated at 12V and 21W.
The 921 bulb, used in the rear fog lights of the 2009-2011 ML63 AMG, is an ANSI-standard T15 wedge bulb rated at 12V and 16W, a lower wattage than the P21W it replaced in this application.
The 921 wedge bulb and the P21W bayonet bulb are not interchangeable, as they use entirely different base designs and originate from separate standardization systems, ANSI and ECE respectively.
All four bulb types specified across both fog light positions on the ML63 AMG operate on a 12V electrical system, consistent with standard automotive voltage.
The H7 and H11 front fog light bulbs both fall under ECE regulation, while the rear fog light bulbs span two different standards, with the P21W under ECE and the 921 under ANSI, reflecting a mix of regional specifications across the model's production years.