Buick LaCrosse Headlight Bulb Size

Additional Notes

• The D3S bulb is the most consistently specified HID type across the LaCrosse range, appearing in both high and low beam positions for the 2017-2019 model years, as well as in HID-equipped versions of the 2014-2016 model years. D3S bulbs are high-intensity discharge units that operate without an external ignition module, as the igniter is integrated directly into the bulb itself.
• The Buick LaCrosse used the D1S bulb type for both high and low beam positions in HID-equipped versions of the 2010-2013 model years. Unlike the D3S, the D1S requires a separate external igniter as part of the ballast assembly, making the two HID types electrically and mechanically incompatible with each other despite their similar appearance.
• The H9 bulb served as the high beam specification for halogen-equipped LaCrosse models from 2005 through 2009, and continued as an option in halogen versions of the 2010-2013 model years. The H9 is a single-filament halogen bulb rated at 65 watts, using a PGJ19-5 base.
• The H11 bulb is specified for the low beam position across all halogen-equipped LaCrosse models from 2005 through 2013. It is a single-filament halogen bulb using a PGJ19-2 base, rated at 55 watts. Although the H9 and H11 share a physically similar housing, their base configurations differ, and the two types are not interchangeable.
• The 9012 bulb replaced both the H9 and H11 in halogen-equipped versions of the 2014-2016 LaCrosse for both high and low beam positions. The 9012 is a dual-function halogen bulb, meaning a single bulb serves both beam functions within the same projector housing, distinguishing it from the separate H9 and H11 arrangement used in earlier halogen configurations.
• For the 2014-2016 Buick LaCrosse, headlamp bulb fitment depended on whether the vehicle was built with halogen capsule headlamps or HID headlamps. These two configurations required entirely different bulb types, with halogen versions using the 9012 and HID versions using the D3S, making the headlamp system type a necessary factor before selecting a replacement bulb.
• A similar split in fitment applied to the 2010-2013 LaCrosse, where halogen-equipped models used the H9 for high beam and H11 for low beam, while HID-equipped models used the D1S for both positions. The high and low beam positions in the HID configuration shared a single bulb type, whereas the halogen configuration required two distinct bulb types.
• The 2013 model year represented a transition point in the LaCrosse headlamp specifications. HID-equipped versions retained the D1S used since 2010, while halogen versions shifted the high beam from the H9 to a continued H9 fitment and the low beam from H11 to H11, with the subsequent 2014 model year introducing the 9012 for halogen variants and the D3S replacing the D1S for HID variants.
• The D1S and D3S bulb types, while both HID discharge types with similar quartz arc tube construction, are not interchangeable. The D1S integrates the igniter within the ballast rather than the bulb, whereas the D3S incorporates the igniter within the bulb itself. Installing a D3S into a system designed for D1S, or vice versa, is not supported by the specifications.
• From 2005 through 2009, the LaCrosse headlamp specifications listed no HID option, with the H9 and H11 as the sole high and low beam bulb types respectively. Beginning with the 2010 model year, an HID variant using the D1S was introduced alongside the continuing halogen option, marking the point at which dual headlamp system configurations first appeared in the LaCrosse specifications.