The Mercedes-Benz 230 front turn signal bulb utilizes either P21/5W or P21W size, while the rear turn signal bulb requires P21W size. The replacement chart covers 1966 to 1978 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 P21W bulb follows the ECE standard used across Europe and worldwide. It is a single-filament signalling bulb rated at 12V and 21W, fitted with a BA15s bayonet base.
The P21/5W also follows the ECE standard. It is a dual-filament signalling bulb rated at 12V with filaments at 21W and 5W, fitted with a BAY15d bayonet base.
The BA15s base of the P21W and the BAY15d base of the P21/5W are not interchangeable. The BAY15d base features offset pins to prevent incorrect installation, while the BA15s base has symmetrically placed pins.
The Mercedes-Benz 230 front turn signal uses two distinct bulb types across its model years. The P21W is specified for 1966-1969 and 1974-1976, while the P21/5W is specified for 1977-1978.
The dual-filament P21/5W used in the 1977-1978 front turn signal positions serves two circuits within a single bulb, a function the single-filament P21W used in earlier years cannot replicate due to its different base design and wiring configuration.
The rear turn signal on the Mercedes-Benz 230 uses the P21W across all listed model years from 1966-1969 and 1974-1978, making it consistent regardless of the front turn signal variation.
The front and rear turn signal positions share the same P21W specification for 1966-1969 and 1974-1976, meaning the same bulb type fits both locations during those years.
For 1977-1978, the front and rear turn signal positions require different bulb types. The front requires the P21/5W with a BAY15d base, while the rear requires the P21W with a BA15s base.