The BMW 335i uses a 12496 bulb size for front turn signal applications and a P21W bulb size for rear turn signal applications. The replacement chart covers 2014 to 2015 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 BMW 335i uses two distinct bulb types across its front and rear turn signal positions for the 2014-2015 model years: the 12496 at the front and the P21W at the rear.
The 12496 is a halogen bulb designated by a Philips/Osram part number rather than a universal standard, indicating it is intended for a specialty application and is not a generic replacement type.
Both the 12496 and P21W operate on a 12V electrical system, consistent with standard automotive low-voltage architecture.
The P21W follows ECE (Economic Commission for Europe) standardization, a regulatory framework recognized across Europe and internationally, which governs the bulb's physical and electrical properties.
The P21W is a single-filament bulb, meaning it serves one lighting function only, which in this context is turn signaling rather than a combined stop/tail role.
The P21W uses a BA15s bayonet base, a single-contact bayonet fitting with a 15mm collar. The "s" designation indicates the contact pins are positioned symmetrically, so the bulb can only be seated in one rotational orientation.
The P21W is rated at 21W, a wattage level standard for dedicated signaling bulbs under ECE regulations.
Because the front position specifies the 12496 by manufacturer part number rather than an ECE or SAE code, substitution with a generically cross-referenced bulb carries a higher risk of incompatibility than with a standardized type like the P21W.