When doing replacement or upgrading on 1988 – 2000 Chevrolet C3500 with 4 rectangular headlamps 2 halogen capsule sealed beam, the bulb size guide is necessary for you to take the reference.
Jump to corresponding car model with the catalog bellow.

Low Beam Headlight 1988 – 1991 H4703
High Beam Headlight 1988 – 1991 H4701
Front Fog Light 1988 – 1991 H3-55W
Back Up Light 1988 – 1989 1156
1990 – 1991 3156
Brake 1988 – 1989 2057
1990 – 1991 3057
Dome Light 1988 – 1989 211-2
1990 – 1991 578
Front Side Marker 1988 – 1989 194
Front Turn Signal 1988 – 1991 2357NA
License Plate 1988 – 1991 194
Parking Light 1988 – 1991 2357
Rear Turn Signal 1988 – 1989 2057
1990 – 1991 3057
Tail Light 1988 – 1989 2057
1990 – 1991 3057
Courtesy 1988 – 1991 1003
Engine Compartment Light 1990 – 1991 1156
Glove Box 1990 – 1991 194
Radio Display 1988 – 1991 1893
High Beam and Low Beam Headlight 1988 – 1991 H6054
Front Fog Light 1988 – 1991 H3-55W
Back Up Light 1988 – 1989 1156
1990 – 1991 3156
Brake 1988 – 1989 2057
1990 – 1991 3057
Dome Light 1988 – 1991 211-2
Front Side Marker 1988 – 1989 194
Front Turn Signal 1988 – 1991 2357NA
License Plate 1988 – 1991 194
Parking Light 1988 – 1991 2357
Rear Turn Signal 1988 – 1989 2057
1990 – 1991 3057
Tail Light 1988 – 1989 2057
1990 – 1991 3057
Courtesy 1988 – 1991 1003
Engine Compartment Light 1990 – 1991 1156
Glove Box 1990 – 1991 194
Radio Display 1988 – 1991 1893
Low Beam Headlight 1990 – 2000 9006
High Beam Headlight 1990 – 2000 9005
Front Fog Light 1999 – 2000 894
1990 – 1991, 1993 – 1998 H3-55W
Back Up Light 1999 – 2000 1156
1990 – 1992 3156
Brake 1990 – 1992 3057
Dome Light 1992 – 1998 211-2
1990 – 1991, 1999 – 2000 578
Front Side Marker 1990 – 2000 194
Front Turn Signal 1993, 1995 – 1997 2357
1990 – 1991, 1994, 1998 – 2000 2357NA
1992 3057
License Plate 1990 – 2000 194
Parking Light 1990 – 1991, 1993 – 2000 2357
1992 3057
Rear Turn Signal 1990 – 1992 3057
Tail Light 1990 – 1992 3057
Luggage Compartment 1993 – 1998 912
1999 – 2000 921
Center High Mount Stop Light 1993 – 2000 921
Courtesy 1990 – 1991 1003
Engine Compartment Light 1990 – 1991 1156
Glove Box 1990 – 1991, 1993 – 2000 194
Map Light 1994, 1997 – 1998 168
1993, 1995 – 1996 194
Radio Display 1990 – 1991 1893
High Beam and Low Beam Headlight 1992 – 2000 H6054
Front Fog Light 1999 – 2000 880
1993 – 1998 H3-55W
Back Up Light 1999 – 2000 1156
1992 3156
Brake 1992 3057
Dome Light 1992 – 1998 211-2
1999 – 2000 578
Front Side Marker 1992 – 2000 194
Front Turn Signal 1993 – 1995, 1998 2357
1996 – 1997, 1999 – 2000 2357NA
1992 3057
License Plate 1992 – 2000 194
Parking Light 1993 – 2000 2357
1992 3057
Rear Turn Signal 1992 3057
Tail Light 1992 3057
Luggage Compartment 1993 – 1998 912
1999 – 2000 921
Center High Mount Stop Light 1993 – 2000 921
Glove Box 1993 – 2000 194
Map Light 1993 – 1998 168