BMW 435i Gran Coupe front turn signal bulbs use PY24WNA size while rear turn signal bulbs use P21W size. Replacement chart data covers 2015 to 2016 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 435i Gran Coupe uses two distinct bulb types across its front and rear turn signal positions for the 2015-2016 model years.
The front turn signal on the 2015-2016 BMW 435i Gran Coupe requires the PY24WNA bulb, which applies specifically to vehicles equipped with HID headlamps.
The PY24WNA is an ANSI-standard bulb rated for the US and Canadian markets, operating at 12 volts and 24 watts with a PGU20-4 base.
The PY24WNA is the amber-specific variant of the ECE PY24W, meaning the bulb envelope itself is amber-tinted rather than relying on a colored lens to produce the required turn signal color.
The PGU20-4 base is a wedge-type base with guide pins, a design that prevents incorrect orientation during installation.
The rear turn signal across both model years uses the P21W, an ECE-standard single-filament bulb rated at 12 volts and 21 watts.
The P21W uses a BA15s bayonet base, where the single contact pin distinguishes it from the dual-contact BA15d variant, making the two physically non-interchangeable despite their similar appearance.
The PY24WNA and P21W operate at different wattages, 24W and 21W respectively, which means the two bulb types are not interchangeable between front and rear positions.
The PY24WNA follows ANSI standards while the P21W follows ECE standards, reflecting the different regulatory frameworks governing automotive lighting in North American versus international markets.
Because the front fitment is conditional on HID headlamp configuration, vehicles with a different headlamp system may not share the same front turn signal bulb specification.