When doing replacement or upgrading on 1976 – 2004 Cadillac Seville 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 Headlight1986 – 1991 9004
1992 – 2000 9006
1976 – 1985 H4656
High Beam Headlight1986 – 1991 9004
1992 – 2000 9005
1976 – 1985 H4651
Front Fog Light1998 – 2000 880
1986 – 1990 881
1992 – 1997 886
Back Up Light1976 – 1989, 1993 – 1999 1156
1992 2057
1990 – 1991 3057
2000 3157
Brake1976 – 1982 1157
1983 – 1997 2057
1999 – 2000 3057
1998 3157
Dome Light1981, 1984 1004
1992 194
1976 – 1980, 1989 – 1991 562
1985 – 1988 912
Front Side Marker1979 1157
1981 – 1983, 1990 – 1994, 1998 – 2000 194
1976 – 1978, 1980, 1985 – 1989, 1995 – 1997 194NA
Front Turn Signal1976 – 1982 1157
1983 – 1991 2057
1992 – 1997 2357NA
1998 – 2000 3157NA
License Plate1981 161
1976 – 1977, 1979 – 1980, 1982 – 2000 194
1978 97
Parking Light1976 – 1982 1157
1983 194
1984 – 1991 2057NA
1993 – 1997 2357
1992 2357NA
1998 – 2000 3157
Rear Side Marker1976 – 1989, 1992 – 1994 194
1990 – 1991 24
Rear Turn Signal1976 – 1982 1157
1983 – 1997 2057
1998 – 2000 3057
Tail Light1976 – 1982 1157
1983 – 1997 2057
1999 – 2000 3057
1998 3157
Center High Mount Stop Light1986 – 1999 1156
Courtesy1979 – 1981 161
1989 – 1994, 1996 – 1999 168
1995 192
1976 – 1978, 1982, 1985 – 1988 562
1983 – 1984 89
Engine Compartment Light1976 – 1981 1003
1982 – 1991 1156
1992 – 2000 561
Glove Box1976 – 1988, 1990 – 1991 1816
1989, 1992 – 2000 194
Map Light1979 – 1980, 1982 – 1988 1004
1992 – 2000 168
1978, 1981 562
1989 – 1991 906
Radio Display1976 – 1977, 1981 – 1982 1895
1979 – 1980 194
Rear Reading Light2000 194
Stepwell2000 562
Trunk1976 – 1993, 1995 1003
2000 211-2
1994, 1996 – 1999 561
Low Beam Headlight2001 – 2004 9006
High Beam Headlight2001 – 2004 9005
Front Fog Light2001 – 2004 880
Back Up Light2001 – 2004 3157
Brake2001 – 2004 3057
Front Side Marker2001 – 2004 194
Front Turn Signal2001 – 2004 4157
License Plate2001 – 2004 194
Parking Light2001 – 2004 4157
Rear Turn Signal2001 – 2004 3057
Tail Light2001 – 2004 3057
Engine Compartment Light2001 – 2004 561
Glove Box2001 – 2004 194
Map Light2001 – 2004 168
Rear Reading Light2001 – 2004 194
Stepwell2001 – 2004 562
Trunk2001 – 2004 211-2
Low Beam Headlight2001 – 2004 D1S
High Beam Headlight2001 – 2004 9005
Front Fog Light2001 – 2004 880
Back Up Light2001 – 2004 3157
Brake2001 – 2004 3057
Front Side Marker2001 – 2004 194
Front Turn Signal2001 – 2004 4157
License Plate2001 – 2004 194
Parking Light2001 – 2004 4157
Rear Turn Signal2001 – 2004 3057
Tail Light2001 – 2004 3057
Engine Compartment Light2001 – 2004 561
Glove Box2001 – 2004 194
Map Light2001 – 2004 168
Rear Reading Light2001 – 2004 194
Stepwell2001 – 2004 562
Trunk2001 – 2004 211-2