When doing replacement or upgrading on 1977 – 2018 BMW 320i xDrive Adaptive 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 Headlight1992 – 1995 9006
1977 – 1983 H5006
High Beam Headlight1992 – 1995 9005
1977 – 1983 H5001
Front Fog Light1992 – 1995 H1
Back Up Light1977 – 1983, 1992 – 1995 1156
Brake1977 – 1983, 1992 – 1994 1156
1995 1157
Dome Light1977 – 1983, 1992 – 1994 578
1995 DE3423
Front Side Marker1995 12961
1992 – 1994 P21/5W
1977 – 1983 T4W
Front Turn Signal1977 – 1983, 1992 – 1995 P21/5W
License Plate1977 – 1983, 1992 – 1995 12844
Parking Light1992 – 1995 1157
1977 – 1983 P21/5W
Rear Side Marker1979 – 1981, 1983 12929
1992 – 1994 P21/4W
1977 – 1978, 1982 T4W
Rear Turn Signal1977 – 1983, 1992 – 1995 1156
Tail Light1995 1157
1977 – 1983 12814
1992 – 1994 12821
Center High Mount Stop Light1992 – 1995 1156
Engine Compartment Light1992 – 1995 578
1977 – 1983 DE3423
Glove Box1977 – 1983 12929
1992 – 1995 DE3423
Map Light1995 6411
Trunk1993 – 1994 6411
1977 – 1983, 1992, 1995 DE3423
Low Beam Headlight2001 – 2005, 2012 – 2018 H7
High Beam Headlight2001 – 2005, 2012 – 2018 H7
Front Fog Light2001 – 2005 9006
2012 – 2018 H8
Back Up Light2001 – 2005, 2012 – 2015 1156
Brake2001 – 2005, 2012 – 2015 1156
Daytime Running Light2014 – 2015 PW24WHTR
Dome Light2004 – 2005, 2012 – 2018 194
2001 DE3423
Front Side Marker2002 – 2005 12961
2001 P21/5W
Front Turn Signal2016 – 2018 3457NA
2012 – 2015 PY21W
License Plate2001 – 2005 12844
Parking Light2001 12961
2002 – 2005 194
2016 – 2018 3457
2012 – 2015 H6W
Rear Side Marker2001 – 2003 P21/4W
Rear Turn Signal2004 – 2005, 2012 – 2015 1156
Tail Light2001 – 2005 P21/4W
Front Inner Turn Signal2001 1156
Front Outer Turn Signal2001 12961
Courtesy2002 – 2005 6418
Glove Box2001 – 2005 DE3423
Map Light2004 – 2005 12961
Stepwell2001 DE3423
Trunk2001 – 2005 6411
Low Beam Headlight2001 D2S
High Beam Headlight2001 H7
High Beam and Low Beam Headlight2012 – 2015 D1S
2002 – 2005 D2S
Front Fog Light2001 – 2005 9006
2012 – 2015 H8
Back Up Light2001 – 2005, 2012 – 2015 1156
Brake2001 – 2005, 2012 – 2015 1156
Daytime Running Light2002 – 2005 H7
Dome Light2004 – 2005, 2012 – 2015 194
2001 DE3423
Front Side Marker2002 – 2005 12961
2001 P21/5W
Front Turn Signal2012 – 2015 PY21W
License Plate2001 – 2005 12844
Parking Light2001 12961
2002 – 2005 194
Rear Side Marker2001 – 2003 P21/4W
Rear Turn Signal2004 – 2005, 2012 – 2015 1156
Tail Light2001 – 2005 P21/4W
Front Inner Turn Signal2001 P21W
Front Outer Turn Signal2001 12961
Courtesy2002 – 2005 6418
Glove Box2001 – 2005 DE3423
Map Light2004 – 2005 12961
Stepwell2001 DE3423
Trunk2001 – 2005 6411
Front Fog Light2012 – 2015 H8
Back Up Light2012 – 2015 1156
Brake2012 – 2015 1156
2016 – 2018 H21W
Dome Light2016 – 2018 12961
2012 – 2015 194
Front Turn Signal2012 – 2015 PY21W
Rear Turn Signal2012 – 2015 1156
Low Beam Headlight2013 – 2018 H7
High Beam Headlight2013 – 2018 H7
Front Fog Light2013 – 2018 H8
Back Up Light2013 – 2015 1156
Brake2013 – 2015 1156
Daytime Running Light2014 – 2015 PW24WHTR
Dome Light2013 – 2018 194
Front Turn Signal2016 – 2018 3457NA
2013 – 2015 PY21W
Parking Light2016 – 2018 3457
2013 – 2015 H6W
Rear Turn Signal2013 – 2015 1156
High Beam and Low Beam Headlight2013 – 2015 D1S
Front Fog Light2013 – 2015 H8
Back Up Light2013 – 2015 1156
Brake2013 – 2015 1156
Dome Light2013 – 2015 194
Front Turn Signal2013 – 2015 PY21W
Rear Turn Signal2013 – 2015 1156
Front Fog Light2013 – 2015 H8
Back Up Light2013 – 2015 1156
Brake2013 – 2015 1156
2016 – 2018 H21W
Dome Light2016 – 2018 12961
2013 – 2015 194
Front Turn Signal2013 – 2015 PY21W
Rear Turn Signal2013 – 2015 1156