The Chevrolet C70 front and rear side marker bulb sizes include 1157 and 194 options, with the bulb size varying by specific model year. The replacement chart covers vehicle production years spanning 1960 to 1988.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 1157 is a dual-filament bulb operating at 12 volts with a BAY15d bayonet base, rated at 21W on its primary filament and 5W on its secondary filament. This dual-filament design allows a single bulb to serve two lighting functions simultaneously, such as running light and turn signal operation.
The 194 is a single-filament miniature wedge bulb of the T10 type, operating at 12 volts and rated at 3.78 watts. Its wedge base design requires no locking mechanism, as the base itself holds the bulb in place within the socket.
The BAY15d bayonet base of the 1157 and the wedge base of the 194 are physically incompatible with each other. A socket designed for one type cannot accept the other, making these two bulbs non-interchangeable regardless of voltage compatibility.
For the Chevrolet C70 front side marker, the 1157 is specified for 1979-1982 and 1985-1988, while the 194 is specified for 1983-1984. This means the front socket type differs between those two production periods.
The rear side marker of the Chevrolet C70 uses the 194 across the majority of listed model years, with the 1157 appearing only for 1986. The 1986 rear socket is therefore not compatible with the 194 bulb used in surrounding years.
Both the 1157 and 194 conform to ANSI standards applicable in the United States and Canada, indicating standardized electrical and physical tolerances across manufacturers producing these bulb types.
The 1157 draws significantly more wattage than the 194, a factor relevant to the load capacity of the vehicle's wiring and any socket rated for the lower-wattage 194 type.