The BMW 640i uses D1S bulbs for both high beam and low beam headlight applications, with this specific bulb size remaining consistent across the model line. The replacement chart covers 2012 through 2015 model years and details the corresponding bulb size specifications for each production year.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The BMW 640i uses the D1S bulb type for both high beam and low beam headlights across the 2012-2015 model years, and all listed configurations require HID headlamps.
The D1S is a High-Intensity Discharge (HID) xenon bulb rated at 85 volts and 35 watts, operating at significantly higher voltage than conventional halogen bulbs, which typically run on 12 volts.
D1S bulbs conform to the ECE standard, a regulatory framework recognized in Europe and internationally, meaning the bulb meets defined photometric and safety requirements for road use in those regions.
The D1S features a PK32d-2 base with an integral ignitor built directly into the bulb unit, which distinguishes it from D2S and similar types where the ignitor is housed separately in the ballast.
Because the ignitor is integrated into the D1S bulb itself, substituting a bulb type with a separate ignitor arrangement is not a direct swap and would affect system compatibility.
The D1S is designed exclusively for projector-type headlamp housings, and fitting it into a reflector-style housing would produce incorrect light distribution on the road.
Since both the high beam and low beam positions on the BMW 640i (2012-2015) share the same D1S specification, a single bulb type serves dual functions within the HID headlamp system.