Mercedes-Benz C63 AMG Turn Signal Bulb Size

Additional Notes

• The front turn signal on the Mercedes-Benz C63 AMG uses the 12174NA bulb for the 2016-2019 model years, all specified under the halogen capsule headlamp condition. The 12174NA is an OEM-designated part number with natural amber glass and a 12V rating.
• The PY24WNA bulb covers the front turn signal position for the 2011-2014 model years, also under the halogen capsule headlamp condition. It follows the ANSI standard applicable in the US and Canada, operates at 12V with a 24W output, and uses a PGU20-4 base. It is the amber variant of the ECE PY24W specification.
• The 3357NA and 3457NA are both T25 wedge-type bulbs with natural amber glass and 12V ratings, used in the front turn signal position for the 2009-2010 and 2008 model years respectively. Despite their similar designation, the 3357NA is a single-filament bulb rated at 27W, while the 3457NA is a dual-filament bulb rated at 27W and 7W. These two bulbs are not interchangeable due to the filament difference.
• The rear turn signal on the C63 AMG uses the 12496 bulb for the 2008-2010 model years. The 12496 is a Philips/Osram part number for a 12V halogen bulb intended for specialty automotive applications.
• The PY21W bulb appears in the rear turn signal position for the 2011 and 2017 model years. It follows the ECE standard used in Europe and worldwide, operates at 12V with a 21W output, and uses a BAU15s bayonet base. The offset pin configuration of the BAU15s base prevents incorrect installation in sockets designed for other bayonet types.
• The rear turn signal for the 2016, 2018, and 2019 model years specifies the 12496 bulb under the halogen capsule headlamp condition, while the 2017 model year specifies the PY21W under the same condition. This means the rear turn signal bulb type is not uniform across the 2016-2019 range despite sharing the same headlamp configuration qualifier.
• The "NA" suffix present in bulb designations such as 12174NA, PY24WNA, 3357NA, and 3457NA denotes natural amber glass. In these bulbs, the amber color is produced by the glass envelope itself rather than by an amber-coated or painted surface, which is a construction distinction relevant to light output consistency over the bulb's service life.
• The PY24WNA and PY21W bulbs use physically distinct base types, PGU20-4 and BAU15s respectively, meaning they are not interchangeable even though both serve amber turn signal functions. The PGU20-4 is a pin-type base, while the BAU15s is a bayonet-type base with an offset pin arrangement.