The Mercedes-Benz CL550 front turn signal requires a PY24WNA bulb size while the rear turn signal uses a 12271NA bulb size. The replacement chart covers 2007 to 2014 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 CL550 front turn signal uses the PY24WNA bulb across all listed model years, spanning 2007-2014.
The PY24WNA is an ANSI-standard bulb rated for use in the United States and Canada, operating at 12 volts and 24 watts with a PGU20-4 base.
The PGU20-4 base is a wedge-style pin configuration specific to the PY24W bulb family, meaning it is not interchangeable with standard wedge or bayonet base bulbs.
The PY24WNA is the North American variant of the ECE PY24W, with the amber color built into the bulb itself rather than relying on an amber lens to produce the required turn signal color.
The rear turn signal on the CL550 uses the 12271NA bulb for model years 2007-2010.
The 12271NA is an OEM part number designation, and its natural amber glass construction means the amber color is produced by the glass envelope of the bulb rather than a coating or external lens filter.
Both the PY24WNA and the 12271NA are amber-producing bulbs, though they achieve this through different constructions and serve different positions on the vehicle.
The rear turn signal specification covers only 2007-2010, while the front turn signal specification extends through 2014, meaning the two sub-parts do not share an identical range of covered model years.
The PY24WNA and 12271NA are not interchangeable with each other, as they differ in wattage rating, base type, and physical form factor.
The 12271NA operates at 12 volts, consistent with the standard automotive electrical system voltage shared by the PY24WNA front turn signal bulb.