ECE standard (Europe & worldwide). Mercury-free HID (xenon) discharge bulb with PK32d-5 base and integral ignitor, for projector-type housings. 42V, 35W.
The D3S is the sole bulb type specified across both the high beam and low beam headlight positions of the Bentley Mulsanne for the 2011-2020 model years.
The D3S is a high-intensity discharge (HID) bulb, meaning it produces light through an electrical arc between two tungsten electrodes rather than through a heated filament.
As an HID type, the D3S requires a ballast to regulate the high voltage needed to strike and sustain the arc, making it incompatible with standard halogen sockets without additional components.
The "S" designation in D3S indicates the bulb has no outer protective glass envelope, meaning the arc tube is exposed and the housing itself serves as the protective enclosure.
D3S bulbs operate without mercury in their gas fill, which distinguishes them from earlier HID generations such as the D1S and D2S and reflects compliance with environmental regulations in effect during the Mulsanne's production run.
Because the Bentley Mulsanne uses D3S for both high and low beam functions across all listed years, the vehicle relies on a projector or bi-xenon lens system to direct the same bulb's output for each lighting mode rather than separate bulbs for each function.
The D3S specification is consistent across the entire 2011-2020 range for both beam positions, indicating no mid-cycle change in headlight bulb fitment occurred during that period.
D3S bulbs are not interchangeable with D1S or D2S types despite their similar appearance, as the base connector and igniter configuration differ between generations.