When doing replacement or upgrading on 1989 - 1994 Audi 100, the bulb size guide is necessary for you to take the reference. Jump to a corresponding car model with the catalog below.  
High Beam and Low Beam Headlight 1989 - 1994 9004
Front Fog Light 1989 - 1994 H3-55W
Back Up Light 1989 - 1994 1156
Brake 1989 - 1994 1157
Dome Light 1989 - 1994 578
Front Side Marker 1989 - 1994 12821
Front Turn Signal 1989 - 1994 P21/5W
License Plate 1989 - 1994 T4W
Parking Light 1989 - 1994 1157
Rear Side Marker 1989 - 1994 12821
Rear Turn Signal 1989 - 1994 1156
Tail Light 1989 - 1994 1157
Center High Mount Stop Light 1989 - 1994 12505
Courtesy 1989 - 1994 12256
Engine Compartment Light 1989 - 1994 578
Glove Box 1989 - 1994 12929
Stepwell 1989 - 1994 12844
Trunk 1989 - 1994 6411

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