When doing replacement or upgrading on 1968 – 1994 Volkswagen Transporter, the bulb size guide is necessary for you to take the reference.
Jump to corresponding car model with the catalog bellow.

High Beam and Low Beam Headlight1968 – 1979, 1985 6014
1986 – 1994 9004
Front Fog Light1986 – 1994 H3-55W
Back Up Light1968 – 1979, 1985 – 1994 1156
Brake1985 1156
1968 – 1979, 1986 – 1994 1157
Dome Light1986 – 1991 578
1985 6411
Front Side Marker1968 – 1979 1895
1985 – 1991 T4W
Front Turn Signal1968 – 1979, 1985, 1992 – 1994 1157
1986 – 1991 P21/5W
License Plate1985 12814
1992 – 1994 194
1968 – 1979 89
1986 – 1991 T4W
Parking Light1968 – 1979, 1985 – 1994 1157
Rear Side Marker1985, 1988 – 1990 12929
1968 – 1979 1895
1986 – 1987, 1991 T4W
Rear Turn Signal1968 – 1979, 1985 – 1994 1156
Tail Light1968 – 1979, 1986 – 1991 1157
1985 12821
1992 – 1994 P21/5W
Center High Mount Stop Light1986 – 1994 194
Courtesy1986 – 1991 6411
Glove Box1990 12818
1986 – 1989, 1991 DE3175