Chevrolet C70 Back Up Light Bulb Size

The Chevrolet C70 back up light requires a single 1156 bulb size for proper illumination and visibility during reverse maneuvers. Available information covers a span of time starting in 1960 and ending in 1988.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1979-1988	1156
1960-1961	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

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Additional Notes

The 1156 is the sole back up light bulb size specified for the Chevrolet C70 across all listed model years.
The 1156 is an ANSI-standard bulb recognized in both the United States and Canada, meaning it conforms to a defined set of electrical and physical standards shared across North American markets.
It is a single-filament bulb, which means it serves one lighting function only, as opposed to dual-filament types that handle two functions such as braking and running light duties simultaneously.
The 1156 uses a BA15s bayonet base, a single-contact mount where the bulb is inserted and twisted to lock into place rather than screwed in.
The bulb operates at 12 volts and draws 21 watts, figures consistent with standard automotive electrical systems of that period.
The specifications cover the 1960-1961 and 1979-1988 model years of the C70, with the 1156 size applying uniformly across both ranges.
Because a single bulb type is specified across all listed years, the 1156 is interchangeable between those model years for the back up light position without modification.