Mercedes-Benz S400 Turn Signal Bulb Size

The Mercedes-Benz S400 front turn signal requires a PY24WNA bulb size for proper operation. The replacement chart covers 2010 through 2013 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.

Front Turn Signal

Years	Bulb Size
2010-2013	PY24WNA

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Amber variant of ECE PY24W with PGU20-4 base. 12V, 24W.	PY24WNA

Other Locations

Additional Notes

The Mercedes-Benz S400 uses the PY24WNA bulb for the front turn signal across the 2010-2013 model years.
The PY24WNA is an ANSI-standard bulb, meaning it conforms to specifications established for the United States and Canadian markets rather than the broader international ECE standard.
It is the amber variant of the ECE PY24W, a distinction that carries practical importance since the amber coloring is built into the bulb itself rather than produced by a colored lens.
The PY24WNA uses a PGU20-4 base, which is an offset pin configuration. This base design is not universally interchangeable with other PGU20 variants, as the pin offset differs between subtypes to prevent incorrect fitment.
The bulb operates at 12 volts and draws 24 watts, placing it in a moderate wattage range typical of incandescent turn signal applications in passenger vehicles of this era.
Because the PY24WNA is the ANSI market version of the PY24W, substituting the standard ECE PY24W in its place would not satisfy North American regulatory requirements for pre-colored amber signal bulbs.