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 Headlight 1992 – 1995 9006
1977 – 1983 H5006
High Beam Headlight 1992 – 1995 9005
1977 – 1983 H5001
Front Fog Light 1992 – 1995 H1
Back Up Light 1977 – 1983, 1992 – 1995 1156
Brake 1977 – 1983, 1992 – 1994 1156
1995 1157
Dome Light 1977 – 1983, 1992 – 1994 578
1995 DE3423
Front Side Marker 1995 12961
1992 – 1994 P21/5W
1977 – 1983 T4W
Front Turn Signal 1977 – 1983, 1992 – 1995 P21/5W
License Plate 1977 – 1983, 1992 – 1995 12844
Parking Light 1992 – 1995 1157
1977 – 1983 P21/5W
Rear Side Marker 1979 – 1981, 1983 12929
1992 – 1994 P21/4W
1977 – 1978, 1982 T4W
Rear Turn Signal 1977 – 1983, 1992 – 1995 1156
Tail Light 1995 1157
1977 – 1983 12814
1992 – 1994 12821
Center High Mount Stop Light 1992 – 1995 1156
Engine Compartment Light 1992 – 1995 578
1977 – 1983 DE3423
Glove Box 1977 – 1983 12929
1992 – 1995 DE3423
Map Light 1995 6411
Trunk 1993 – 1994 6411
1977 – 1983, 1992, 1995 DE3423
Low Beam Headlight 2001 – 2005, 2012 – 2018 H7
High Beam Headlight 2001 – 2005, 2012 – 2018 H7
Front Fog Light 2001 – 2005 9006
2012 – 2018 H8
Back Up Light 2001 – 2005, 2012 – 2015 1156
Brake 2001 – 2005, 2012 – 2015 1156
Daytime Running Light 2014 – 2015 PW24WHTR
Dome Light 2004 – 2005, 2012 – 2018 194
2001 DE3423
Front Side Marker 2002 – 2005 12961
2001 P21/5W
Front Turn Signal 2016 – 2018 3457NA
2012 – 2015 PY21W
License Plate 2001 – 2005 12844
Parking Light 2001 12961
2002 – 2005 194
2016 – 2018 3457
2012 – 2015 H6W
Rear Side Marker 2001 – 2003 P21/4W
Rear Turn Signal 2004 – 2005, 2012 – 2015 1156
Tail Light 2001 – 2005 P21/4W
Front Inner Turn Signal 2001 1156
Front Outer Turn Signal 2001 12961
Courtesy 2002 – 2005 6418
Glove Box 2001 – 2005 DE3423
Map Light 2004 – 2005 12961
Stepwell 2001 DE3423
Trunk 2001 – 2005 6411
Low Beam Headlight 2001 D2S
High Beam Headlight 2001 H7
High Beam and Low Beam Headlight 2012 – 2015 D1S
2002 – 2005 D2S
Front Fog Light 2001 – 2005 9006
2012 – 2015 H8
Back Up Light 2001 – 2005, 2012 – 2015 1156
Brake 2001 – 2005, 2012 – 2015 1156
Daytime Running Light 2002 – 2005 H7
Dome Light 2004 – 2005, 2012 – 2015 194
2001 DE3423
Front Side Marker 2002 – 2005 12961
2001 P21/5W
Front Turn Signal 2012 – 2015 PY21W
License Plate 2001 – 2005 12844
Parking Light 2001 12961
2002 – 2005 194
Rear Side Marker 2001 – 2003 P21/4W
Rear Turn Signal 2004 – 2005, 2012 – 2015 1156
Tail Light 2001 – 2005 P21/4W
Front Inner Turn Signal 2001 P21W
Front Outer Turn Signal 2001 12961
Courtesy 2002 – 2005 6418
Glove Box 2001 – 2005 DE3423
Map Light 2004 – 2005 12961
Stepwell 2001 DE3423
Trunk 2001 – 2005 6411
Front Fog Light 2012 – 2015 H8
Back Up Light 2012 – 2015 1156
Brake 2012 – 2015 1156
2016 – 2018 H21W
Dome Light 2016 – 2018 12961
2012 – 2015 194
Front Turn Signal 2012 – 2015 PY21W
Rear Turn Signal 2012 – 2015 1156
Low Beam Headlight 2013 – 2018 H7
High Beam Headlight 2013 – 2018 H7
Front Fog Light 2013 – 2018 H8
Back Up Light 2013 – 2015 1156
Brake 2013 – 2015 1156
Daytime Running Light 2014 – 2015 PW24WHTR
Dome Light 2013 – 2018 194
Front Turn Signal 2016 – 2018 3457NA
2013 – 2015 PY21W
Parking Light 2016 – 2018 3457
2013 – 2015 H6W
Rear Turn Signal 2013 – 2015 1156
High Beam and Low Beam Headlight 2013 – 2015 D1S
Front Fog Light 2013 – 2015 H8
Back Up Light 2013 – 2015 1156
Brake 2013 – 2015 1156
Dome Light 2013 – 2015 194
Front Turn Signal 2013 – 2015 PY21W
Rear Turn Signal 2013 – 2015 1156
Front Fog Light 2013 – 2015 H8
Back Up Light 2013 – 2015 1156
Brake 2013 – 2015 1156
2016 – 2018 H21W
Dome Light 2016 – 2018 12961
2013 – 2015 194
Front Turn Signal 2013 – 2015 PY21W
Rear Turn Signal 2013 – 2015 1156