The Mercedes-Benz 230 uses a P21/5W bulb size for front side marker applications and a 3893 bulb size for rear side marker positions. 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 Mercedes-Benz 230 side marker specifications cover two distinct bulb types across all listed model years: the P21/5W and the 3893. Both share the BAY15d bayonet base and dual-filament construction, though they originate from different standardization systems.
The P21/5W follows the ECE standard, which governs lighting equipment across Europe and much of the world. It operates at 12V with a 21W main filament and a 5W secondary filament, making the wattage split explicit in its designation.
The 3893 follows the ANSI standard used in the United States and Canada. It is classified as a specialty application bulb and operates at 12V, though its wattage values are not broken out in the designation the way they are in the P21/5W naming convention.
Despite sharing the BAY15d bayonet base, the P21/5W and 3893 are not confirmed as interchangeable within these specifications. The two standards impose different performance and dimensional requirements, and substitution between them is not indicated here.
The front side marker on the Mercedes-Benz 230 used the P21/5W for the 1977-1978 model years, while the 3893 was specified for 1968-1969 and 1974-1976.
The rear side marker used the 3893 exclusively across all listed years, spanning 1966-1969 and 1974-1978, with no P21/5W fitment recorded for that position.
The BAY15d base type found on both bulbs is a double-contact bayonet fitting. The offset pins on this base prevent incorrect single-filament bulbs from being seated in sockets designed for dual-filament operation.
The front side marker position shows a bulb type change between the 1976 and 1977 model years, shifting from the ANSI-standard 3893 to the ECE-standard P21/5W.
The 3893 is the dominant bulb type across the full set of specifications, appearing in every rear side marker position and in the majority of front side marker positions as well.
A gap exists in the listed model years between 1969 and 1974 for both the front and rear side marker positions, with no bulb size data recorded for the years in between.