The Mercedes-Benz 190E brake light utilizes a P21W bulb size for illumination. Available information covers the span from 1984 through 1993 for the specified automotive lighting component.
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 190E, covering both the standard brake lights for 1984-1993 and the Center High Mount Stop Light for 1987-1993.
P21W is an ECE-standardized bulb type, meaning it conforms to the Economic Commission for Europe regulatory framework used across European and international automotive markets.
The P21W operates at 12 volts with a 21-watt output, which is a standard rating for single-filament signalling applications in passenger vehicles.
The BA15s bayonet base on the P21W is a single-contact bayonet fitting. The "s" in BA15s denotes a single contact at the base, distinguishing it from the dual-contact BA15d variant, which is not specified here.
Because the P21W is single-filament, it serves a dedicated on/off signalling function. It does not combine brake and tail light duties within a single bulb, unlike dual-filament types such as the P21/5W.
The consistent use of P21W across every listed model year for the standard brake lights means the bulb specification remained unchanged throughout the entire 1984-1993 production span covered by these specifications.
When sourcing a replacement P21W, the BA15s base type is a critical fitment factor. A bulb with a BA15d base will not seat correctly in a BA15s socket, as the two base types are physically incompatible despite their similar appearance.
The 21-watt rating of the P21W is a fixed characteristic of the bulb type. Installing a P21W variant with a different wattage would fall outside the specification and could affect circuit load calculations for the vehicle's electrical system.