The Mercedes-Benz R500 front fog light uses H7 and H11 bulb sizes, while the rear fog light requires a P21W bulb size. The replacement chart covers 2006 to 2007 vehicle 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 R500 front fog light uses different bulb types depending on the model year. The 2007 model year takes an H7 bulb, while the 2006 model year takes an H11 bulb. These two bulb types are not interchangeable, as they use different base fittings.
The H7 is a single-filament halogen bulb operating at 12V and 55W. It uses a PX26d base and conforms to ECE standards, with approval also extended to the US and Japan.
The H11 is likewise a single-filament halogen bulb rated at 12V and 55W. It uses a PGJ19-2 base and conforms to ECE standards, with approval also extended to the US. Despite sharing the same wattage as the H7, the differing base type makes the two bulbs physically incompatible with each other.
The rear fog light on the Mercedes-Benz R500 uses a P21W bulb for both the 2006 and 2007 model years, making it consistent across those two years unlike the front fog light.
The P21W is a single-filament signalling bulb rated at 12V and 21W. It uses a BA15s bayonet base and conforms to ECE standards. Its lower wattage compared to the H7 and H11 reflects its role as a signalling bulb rather than an illumination bulb.
The BA15s bayonet base of the P21W is a single-contact base, which is a common fitment in automotive signalling applications. It differs structurally from the pin-type bases used by the H7 and H11, meaning no cross-compatibility exists between the rear fog bulb and the front fog bulbs.
All three bulb types listed in the R500 fog light specifications conform to ECE (Economic Commission for Europe) standards, indicating suitability for use in markets that require internationally recognized lighting regulations.