The Mercedes-Benz E300 brake light requires a P21W bulb size for proper installation and function. Data for the specified lighting component covers the range from 1995 to 1999.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The P21W is the sole bulb type specified across all brake light positions on the Mercedes-Benz E300, covering both the standard brake lights and the center high mount stop light for the 1995-1999 model years.
The P21W is an ECE-standard single-filament bulb rated at 12 volts and 21 watts, designed primarily for signalling functions such as braking indicators.
The P21W uses a BA15s bayonet base, which is a single-contact bayonet fitting. The "s" in BA15s denotes a single contact point at the base, distinguishing it from dual-contact variants.
Because the BA15s base is a single-contact design, it is not interchangeable with the BA15d base, which carries two contact points and serves dual-filament applications. Substituting one for the other is not possible without modification.
The ECE designation on the P21W indicates compliance with United Nations Economic Commission for Europe regulations, a standard widely adopted across European and international vehicle markets.
The same P21W specification applies to both the standard brake light and the center high mount stop light on the Mercedes-Benz E300, meaning both positions draw on an identical bulb type across the full 1995-1999 range.
At 21 watts, the P21W produces a relatively high output for a single-filament signal bulb, which is a characteristic that distinguishes it from lower-wattage alternatives sometimes used in parking or tail light roles.