The Mercedes-Benz 280 front and rear turn signal bulbs both utilize a P21W size. The replacement chart covers 1973 to 1976 production years with corresponding bulb specifications.
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 for the Mercedes-Benz 280 across all listed turn signal positions and model years.
P21W is an ECE-standard single-filament bulb rated at 12 volts and 21 watts, designed for signalling applications such as turn indicators.
The BA15s base is a single-contact bayonet fitting, meaning it is not interchangeable with dual-contact bayonet bases such as the BA15d, despite sharing the same physical collar size.
The P21W specification applies to both the front and rear turn signal positions on the 280 for the 1973-1976 model years.
Because the front and rear positions share the same bulb type, a single P21W unit serves both locations without fitment variation across those positions.
The ECE designation indicates the P21W conforms to United Nations Economic Commission for Europe lighting regulations, a standard adopted across European and many worldwide markets.
At 21 watts, the P21W produces a relatively high output for a single-filament signal bulb, which is consistent with the visibility requirements typical of turn indicator circuits.