Mercedes-Benz G63 AMG front and rear turn signal bulbs use a 12496 PY21W bulb size. The replacement chart covers 2013 to 2018 production years with bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The PY21W is an ECE-standardized single-filament amber bulb rated at 12V and 21W, fitted with a BAU15s bayonet base. The BAU15s base uses offset pins to prevent incorrect installation of clear bulbs in positions requiring amber output.
The designation 12496 is a Philips/Osram part number for a halogen bulb intended for specialty automotive applications, operating at 12V. Unlike the PY21W, it is identified by a manufacturer part number rather than an ECE type designation.
Both bulb types share a 12V operating voltage, making them electrically compatible with the same vehicle electrical system, though they are not interchangeable due to differing base types and form factors.
The BAU15s base of the PY21W is distinct from the more common BA15s base. The offset pin arrangement of the BAU15s is a deliberate fitment control, meaning a BA15s bulb cannot be seated correctly in a BAU15s socket.
On the Mercedes-Benz G63 AMG, the front turn signal position does not use a consistent bulb type across model years. The 2013-2014 and 2016-2017 model years use the PY21W, while 2015 and 2018 use the 12496.
The rear turn signal position on the G63 AMG similarly alternates between bulb types across model years, with 2013 and 2017-2018 using the 12496, and 2014-2016 using the PY21W.
Because the front and rear turn signal positions do not always share the same bulb type within a given model year, the two positions require separate verification before replacement. For example, the 2017 model year uses PY21W at the front and 12496 at the rear.
The PY21W bulb's amber glass envelope is part of its ECE type approval. Substituting a clear single-filament bulb of otherwise similar ratings would not satisfy the amber output requirement defined by the ECE standard.