When doing replacement or upgrading on 1975 – 1989 Buick Skyhawk, the bulb size guide is necessary for you to take the reference.
Jump to corresponding car model with the catalog bellow.

Low Beam Headlight1975 – 1978, 1982 – 1988 H4656
1989 H4703
High Beam Headlight1975 – 1978, 1982 – 1988 H4651
1989 H4701
High Beam and Low Beam Headlight1979 – 1980 H6054
Front Fog Light1986 – 1989 H3-55W
Back Up Light1975 – 1980, 1982 – 1989 1156
Brake1975 – 1980, 1982 – 1983 1157
1984 – 1989 2057
Dome Light1975 – 1980, 1982 – 1987 561
1988 562
1989 578
Front Side Marker1975 – 1980, 1982 – 1989 194
Front Turn Signal1975 – 1980, 1982 – 1984 1157
1985 – 1989 2057
License Plate1975 – 1980, 1982 – 1989 194
Parking Light1975 – 1980, 1982 – 1985 1157
1986 – 1989 2057
Rear Side Marker1975 – 1980, 1982 – 1989 194
Rear Turn Signal1980 1156
1975 – 1979, 1982 – 1983 1157
1984 – 1989 2057
Tail Light1975 – 1980, 1982 – 1983 1157
1984 – 1989 2057
Center High Mount Stop Light1988 – 1989 1156
1986 – 1987 912
Courtesy1982 – 1989 168
1977 1893
1979 194
1975 – 1976 562
Engine Compartment Light1976 – 1979 1003
1980, 1982 – 1987 1156
1988 – 1989 89
Glove Box1980 1891
1975 – 1979 1893
1985 – 1988 194
Map Light1989 1003
1980 1004
1988 562
1982 – 1987 90
Radio Display1975 – 1976 1816
1978 1893
1979 – 1980, 1982 – 1987 194
Trunk1975 – 1976, 1980, 1982 – 1987 1003
1988 – 1989 89