Mercedes-Benz E300 Back Up Light Bulb Size

Mercedes-Benz E300 back up light bulbs utilize either PY21W or P21W bulb sizes depending on production specifications. The replacement chart covers vehicle data spanning from 1995 to 2019.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
2019	PY21W
1995-1999	P21W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Single-filament amber bulb with BAU15s bayonet base. 12V, 21W.	PY21W
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W

Other Locations

Additional Notes

The Mercedes-Benz E300 backup light specifications cover two bulb types across the listed model years: the P21W and the PY21W.
Both the P21W and PY21W operate at 12 volts and 21 watts, and both are single-filament bulbs governed by ECE standards used in European and worldwide automotive applications.
The P21W uses a BA15s bayonet base, while the PY21W uses a BAU15s bayonet base. Although these two base types are visually similar, they are not interchangeable due to a physical offset in the BAU15s pin alignment that prevents incorrect installation.
The key distinction between the two bulbs is their light color. The PY21W produces amber light, whereas the P21W produces clear light. This difference is relevant to compliance with regional lighting regulations.
The Mercedes-Benz E300 (1995-1999) uses the P21W bulb for the backup light position.
The 2019 Mercedes-Benz E300 uses the PY21W for the same backup light position, representing a different bulb type from the earlier generation.
Because the 2019 model requires a PY21W and the 1995-1999 models require a P21W, bulbs sourced for one generation are not suitable replacements for the other, despite sharing identical wattage and voltage ratings.