Chevrolet Corvair Clock Light Bulb Size

The Chevrolet Corvair clock light utilizes bulb size 1816 and bulb size 57 for the specified interior illumination components. Data for the bulb sizes covers the range from 1960 through 1964.

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
1961-1964	1816
1960	57

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T3.25). 12V, 4W.	1816
ANSI standard (US & Canada). Single-filament bulb with BA9s base. 12V, 1W.	57

Other Locations

Additional Notes

The 1816 bulb is an ANSI-standard miniature wedge type with a T3.25 envelope, rated at 12 volts and 4 watts. The T3.25 designation refers to a tubular glass envelope measuring roughly 3.25 eighths of an inch in width.
The 57 bulb is an ANSI-standard single-filament type fitted with a BA9s bayonet base, rated at 12 volts and 1 watt. The BA9s base is a small-pin bayonet fitting with a 9mm cap body, commonly found in low-current indicator and instrument applications.
The Chevrolet Corvair clock light uses the 1816 bulb across the 1961-1964 model years, making it the predominant bulb type in this specification set.
The 1960 Chevrolet Corvair clock light uses the 57 bulb rather than the 1816, indicating a base-type change between the 1960 and 1961 model years.
The 1816 and 57 bulbs are not interchangeable. The 1816 uses a wedge base while the 57 uses a BA9s bayonet base, and the two also differ in wattage, with the 1816 rated at 4 watts and the 57 rated at 1 watt.
Both bulb types operate on a 12-volt circuit, consistent with the 12-volt electrical systems standard in production vehicles of this era.
Both the 1816 and 57 are classified under ANSI standards applicable in the United States and Canada, meaning their physical and electrical ratings conform to a shared North American specification framework.