When doing replacement or upgrading on 1978 – 1988 Audi 5000 4000 Quattro CS S, the bulb size guide is necessary for you to take the reference.
Jump to corresponding car model with the catalog bellow.

Low Beam Headlight1980 – 1981 4652
1982 – 1984 H4656
High Beam Headlight1980 – 1984 H4651
High Beam and Low Beam Headlight1985 – 1987 9004
Back Up Light1980 – 1987 1156
Brake1980 – 1987 1156
Dome Light1980 – 1981, 1985 – 1987 578
1982 – 1984 6411
Front Side Marker1980 – 1987 12256
Front Turn Signal1982 – 1984 1157
1980 – 1981, 1985 – 1987 P21/5W
License Plate1980 – 1987 T4W
Parking Light1980 – 1987 1157
Rear Side Marker1982 – 1987 12814
1980 – 1981 12929
Rear Turn Signal1980 – 1987 1156
Tail Light1980 – 1987 12814
Center High Mount Stop Light1985 – 1987 194
Trunk1985 – 1987 DE3423
Low Beam Headlight1984 H4656
High Beam Headlight1984 H4651
High Beam and Low Beam Headlight1985 – 1987 9004
Back Up Light1984 – 1987 1156
Brake1984 – 1987 1156
Dome Light1985 – 1987 578
1984 6411
Front Side Marker1984 – 1987 12256
Front Turn Signal1984 1157
1985 – 1987 P21/5W
License Plate1984 – 1987 T4W
Parking Light1984 – 1987 1157
Rear Side Marker1984 – 1987 12814
Rear Turn Signal1984 – 1987 1156
Tail Light1984 – 1987 12814
Center High Mount Stop Light1985 – 1987 194
Trunk1985 – 1987 DE3423
Low Beam Headlight1980 – 1985 4652
1978 – 1979 H5006
High Beam Headlight1980 – 1985 H4651
1978 – 1979 H5001
High Beam and Low Beam Headlight1986 – 1987 9004
Back Up Light1978 – 1979 1073
1980 – 1987 1156
Brake1980 – 1985 1156
1978 – 1979, 1986 – 1987 1157
Dome Light1980 – 1987 578
Front Side Marker1980 – 1985 12256
1986 – 1987 12821
1979 1816
1978 194
Front Turn Signal1978 – 1979 1157
1980 – 1987 P21/5W
License Plate1978 – 1979 1816
1980 – 1987 T4W
Parking Light1978 – 1987 1157
Rear Side Marker1980 – 1981, 1983, 1985 12929
1978 – 1979 1816
1982, 1984 T4W
Rear Turn Signal1978 – 1987 1156
Tail Light1980 – 1987 12814
Center High Mount Stop Light1986 – 1987 194
Courtesy1986 – 1987 6418
Engine Compartment Light1986 – 1987 12814
Glove Box1986 – 1987 12256
Inner Tail Light1978 – 1979 67
Outer Tail Light1978 – 1979 1157
Trunk1986 – 1987 DE3423
High Beam and Low Beam Headlight1988 9004
Front Fog Light1988 H3-55W
Back Up Light1988 P21W
Brake1988 1157
Dome Light1988 578
Front Side Marker1988 12256
Front Turn Signal1988 P21W
License Plate1988 T4W
Parking Light1988 12814
Rear Turn Signal1988 1156
Center High Mount Stop Light1988 12961
Engine Compartment Light1988 T4W
Glove Box1988 12256
Inner Tail Light1988 12821
Outer Tail Light1988 1157
Trunk1988 DE3423
High Beam and Low Beam Headlight1988 9004
Front Fog Light1988 H3-55W
Back Up Light1988 1156
Brake1988 1157
Dome Light1988 578
Front Side Marker1988 12814
Front Turn Signal1988 P21W
License Plate1988 T4W
Parking Light1988 12814
Rear Turn Signal1988 1156
Center High Mount Stop Light1988 12961
Engine Compartment Light1988 T4W
Glove Box1988 12256
Inner Tail Light1988 12821
Outer Tail Light1988 1157
Trunk1988 DE3423
High Beam and Low Beam Headlight1986 – 1987 9004
Back Up Light1986 – 1987 1156
Brake1986 – 1987 1157
Dome Light1986 – 1987 578
Front Side Marker1986 – 1987 12821
Front Turn Signal1986 – 1987 P21/5W
License Plate1986 – 1987 T4W
Parking Light1986 – 1987 1157
Rear Turn Signal1986 – 1987 1156
Tail Light1986 – 1987 12814
Center High Mount Stop Light1986 – 1987 194
Courtesy1986 – 1987 6418
Engine Compartment Light1986 – 1987 12814
Glove Box1986 – 1987 12256
Trunk1986 – 1987 DE3423
High Beam and Low Beam Headlight1988 9004
Front Fog Light1988 H3-55W
Back Up Light1988 P21W
Brake1988 1157
Dome Light1988 578
Front Side Marker1988 12256
Front Turn Signal1988 P21W
License Plate1988 T4W
Parking Light1988 12814
Rear Turn Signal1988 1156
Center High Mount Stop Light1988 12961
Engine Compartment Light1988 T4W
Glove Box1988 12256
Inner Tail Light1988 12821
Outer Tail Light1988 1157
Trunk1988 DE3423
High Beam and Low Beam Headlight1988 9004
Front Fog Light1988 H3-55W
Back Up Light1988 1156
Brake1988 1157
Dome Light1988 578
Front Side Marker1988 12814
Front Turn Signal1988 P21W
License Plate1988 T4W
Parking Light1988 12814
Rear Turn Signal1988 1156
Center High Mount Stop Light1988 12961
Engine Compartment Light1988 T4W
Glove Box1988 12256
Inner Tail Light1988 12821
Outer Tail Light1988 1157
Trunk1988 DE3423