The Mercedes-Benz S550 front turn signal requires a PY24WNA bulb size while the rear turn signal uses a 12271NA bulb size. The replacement chart covers 2007 to 2013 model 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 PY24WNA is the front turn signal bulb for the Mercedes-Benz S550 across the 2007-2013 model years, representing consistent fitment across the entire generation covered by these specifications.
The PY24WNA operates at 12 volts and 24 watts, placing it in a moderate wattage range typical of incandescent front turn signal applications.
PY24WNA follows the ANSI standard applicable to the United States and Canada, distinguishing it from its ECE counterpart, the PY24W, which serves markets outside North America.
Although the PY24WNA is functionally derived from the ECE PY24W, the two are not interchangeable without verification, as ANSI and ECE standards can differ in photometric and regulatory requirements.
The PY24WNA uses a PGU20-4 base, a bayonet-style socket with offset pins designed to allow only one insertion orientation, which prevents incorrect installation.
The amber color of the PY24WNA is produced by the glass envelope itself rather than a coating, which is the defining characteristic of the "NA" (natural amber) designation.
The rear turn signal bulb for the 2007-2008 Mercedes-Benz S550 carries the part number 12271NA, an OEM designation rather than a standardized ANSI or ECE code.
The 12271NA also uses natural amber glass to produce its amber output, consistent with the same coloring method used in the PY24WNA front bulb.
The 12271NA is specified at 12 volts, matching the vehicle's standard electrical system voltage, though its wattage is not listed in these specifications.
Because the 12271NA is identified by an OEM part number rather than a universal bulb code, cross-referencing with aftermarket equivalents requires matching that specific designation to confirm fitment compatibility.