BMW X4 front turn signal bulbs use PY24WNA, 12180, or PY21W sizes, while rear turn signal bulbs use 12182 size for replacement. The chart covers 2015 to 2021 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 BMW X4 front turn signal uses five distinct bulb sizes across the 2015-2021 model years, reflecting both regional lighting standards and headlamp configuration differences.
PY21W is an ECE-standard single-filament amber bulb with a BAU15s bayonet base, rated at 12V and 21W. It appears in the BMW X4 front turn signal position for the 2015, 2017, and 2018 model years, each time specifically in vehicles equipped with HID headlamps.
PY24WNA follows the ANSI standard used in the United States and Canada. It is the amber variant of the ECE PY24W bulb and uses a PGU20-4 base, rated at 12V and 24W. The BMW X4 uses this bulb in the 2021 front turn signal position.
The BAU15s base of the PY21W is offset, meaning it is not interchangeable with the more common BA15s base used in many other automotive bulbs. Substituting an incorrect base type would result in a misfit.
The PGU20-4 base of the PY24WNA is a push-and-turn style connector distinct from bayonet-type bases, making it incompatible with sockets designed for PY21W or similar bayonet-mount bulbs.
Philips part numbers 12180 and 12496 are both 12V halogen bulbs for specialty applications. The 2019 X4 front turn signal uses the 12180, while the 2016 model with HID headlamps uses the 12496.
The rear turn signal of the BMW X4 uses the Philips 12182 across the 2015-2018 model years without variation, indicating a consistent socket specification in that position throughout that generation.
The 12182 is a 12V halogen bulb designated for specialty automotive applications. Its consistent use across four rear turn signal model years suggests stable socket and housing design in that assembly.
The front turn signal of the 2016 BMW X4 with HID headlamps uses the 12496, while the 2015, 2017, and 2018 HID-equipped models use the PY21W. These two bulbs are not interchangeable despite sharing the same headlamp configuration context.
Regional lighting regulations account for the difference between PY21W and PY24WNA. The ECE-standard PY21W is rated at 21W, while the ANSI-standard PY24WNA is rated at 24W, and the two standards use different base designs that prevent cross-substitution.