The Mercedes-Benz 300TE uses a P21/5W bulb size for the front turn signal and a P21W bulb size for the rear turn signal. The replacement chart covers vehicle production spanning 1988 to 1993.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz 300TE uses two distinct bulb types across its turn signal positions: P21/5W for the front and P21W for the rear, both governed by ECE standards recognized across Europe and worldwide markets.
The P21/5W is a dual-filament bulb, meaning it carries two separate filaments within a single envelope, allowing it to serve more than one lighting function simultaneously, such as turn signaling combined with a parking or running light.
The P21W is a single-filament bulb, dedicated to one lighting function, which in this case is the rear turn signal.
Both bulb types operate on a 12V electrical system, consistent with standard automotive voltage across this era of production.
The P21/5W is rated at 21W and 5W, corresponding to its two filaments, while the P21W is rated at a single 21W output.
The P21/5W uses a BAY15d bayonet base, which features offset pins to prevent incorrect installation, ensuring the dual filaments are aligned to their correct circuits.
The P21W uses a BA15s bayonet base, a single-contact fitting that is physically incompatible with the BAY15d socket used by the P21/5W, making the two bulbs non-interchangeable despite their similar appearance.
The front turn signal position on the Mercedes-Benz 300TE requires the P21/5W across all model years from 1988-1993, indicating a consistent fitment throughout the entire production span covered by these specifications.
The rear turn signal position likewise uses the P21W without variation across the same 1988-1993 model year range.
Because the BA15s and BAY15d bases differ in pin alignment, substituting a P21W in a P21/5W socket, or vice versa, is not physically possible without modification, making base type a critical factor in fitment.