When doing replacement or upgrading on 2005 – 2018 Buick LaCrosse capsule halogen headlamps HID with, the bulb size guide is necessary for you to take the reference.
Jump to corresponding car model with the catalog bellow.

Low Beam Headlight2005 – 2009 H11
High Beam Headlight2005 – 2009 H9
High Beam and Low Beam Headlight2017 – 2018 D3S
Front Fog Light2005 – 2009, 2017 – 2018 H8/H11/H16
Back Up Light2005 – 2009, 2017 – 2018 921
Brake2005 – 2009 3057
2017 – 2018 7440
Daytime Running Light2005 – 2009 H8/H11/H16
Dome Light2005 – 2009 194
Front Side Marker2005 – 2009 194
Front Turn Signal2005 – 2009 4157
License Plate2005 – 2009, 2017 – 2018 194
Parking Light2005 – 2009 4157
Rear Side Marker2005 – 2009 194
Rear Turn Signal2005 – 2009 3057
2017 – 2018 7440
Courtesy2005 – 2009 194
Glove Box2005 – 2009 194
Inner Tail Light2005 – 2009 194
Map Light2005 – 2009 168
Outer Tail Light2005 – 2009 3057
Trunk2005 – 2009 912
Low Beam Headlight2010 – 2013 H11
High Beam Headlight2010 – 2013 H9
High Beam and Low Beam Headlight2014 – 2016 9012
Front Fog Light2014 – 2016 H8
2010 – 2013 H8/H11/H16
Back Up Light2010 – 2016 921
Daytime Running Light2014 – 2016 7443
2010 – 2013 H11
Dome Light2010 – 2013 194
Front Side Marker2010 – 2013 3757NA
2014 – 2016 7443
Front Turn Signal2010 – 2013 3757NA
2014 – 2016 7444NA
License Plate2010 – 2016 194
Parking Light2010 – 2013 3757NA
2014 – 2016 7443NA
Rear Turn Signal2010 – 2013 3757NA
2014 – 2016 7440NA
Glove Box2010 – 2013 194
Interior Door2010 – 2016 194
Map Light2014 – 2016 12961
High Beam and Low Beam Headlight2010 – 2013 D1S
2014 – 2016 D3S
Front Fog Light2014 – 2016 H8
2010 – 2013 H8/H11/H16
Back Up Light2010 – 2016 921
Daytime Running Light2010 – 2013 3157
Dome Light2010 – 2013 194
Front Side Marker2010 – 2013 3757NA
Front Turn Signal2010 – 2013 3757NA
2014 – 2016 7444NA
License Plate2010 – 2016 12961
Parking Light2010 – 2013 3757NA
2014 – 2016 7443NA
Rear Turn Signal2010 – 2013 3757NA
2014 – 2016 7440NA
Glove Box2010 – 2013 194
Interior Door2010 – 2016 194
Map Light2014 – 2016 12961