Chevrolet Brookwood Clock Light Bulb Size

The Chevrolet Brookwood clock light requires bulb sizes 194, 1816, 257, and 57 depending on the specific application. Data for the bulb sizes covers the range from 1958 to 1970.

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
1969-1970	194
1961	1816
1959-1960	257
1959-1960	57
1958	57

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 3.78W.	194
ANSI standard (US & Canada). Miniature wedge bulb (T3.25). 12V, 4W.	1816
ANSI standard (US & Canada). Festoon or BA9s base instrument bulb. 12V, 2W.	257
ANSI standard (US & Canada). Single-filament bulb with BA9s base. 12V, 1W.	57

Other Locations

Additional Notes

The 194 bulb is the most frequently specified clock light bulb in the Chevrolet Brookwood, covering the 1969-1970 model years. It is an ANSI-standard miniature wedge bulb in the T10 form factor, rated at 12V and 3.78W.
The 1958-1960 model years rely on the 57 bulb, an ANSI-standard single-filament bulb with a BA9s bayonet base, rated at 12V and 1W. The BA9s base is a small-pin bayonet fitting commonly found in instrument panel applications.
The 257 bulb shares the 1959-1960 model years alongside the 57, and is rated at 12V and 2W. It is specified as either a festoon or BA9s base instrument bulb, meaning the physical mounting style may vary depending on the socket configuration in the vehicle.
The dual-bulb specification for the 1959-1960 Chevrolet Brookwood, listing both the 57 and 257, indicates that two distinct socket types were present in the clock lighting assembly during those years, and the bulbs are not interchangeable with each other due to differing wattage and potentially differing base configurations.
The 1961 model year uses the 1816 bulb exclusively, an ANSI-standard miniature wedge bulb in the T3.25 form factor, rated at 12V and 4W. The T3.25 designation refers to the tubular envelope width expressed in eighths of an inch, making it physically smaller than the T10 used in the 194.
The 194 (T10 wedge) and 1816 (T3.25 wedge) are both wedge-base bulbs but are not interchangeable. Their differing envelope sizes and wattage ratings correspond to different socket housings across the model years in which they appear.
All four bulb types listed across the Brookwood specifications conform to ANSI standards applicable in both the United States and Canada, indicating consistent regulatory classification across the range.
The 57 bulb, at 1W, is the lowest-wattage bulb in the specifications, while the 1816, at 4W, is the highest. This wattage variation across model years reflects differences in the clock illumination circuit design rather than a standardized output level.