Chevrolet Brookwood Radio Display Bulb Size

Additional Notes

• The Chevrolet Brookwood radio display bulb specifications cover model years 1958-1961 and 1969-1972, with three distinct bulb types appearing across those years: the 1816, 1893, and 1891.
• The 1891 and 1893 are both ANSI-standard miniature wedge bulbs rated at 12V and 2W, sharing the same T5 envelope designation. Despite their near-identical electrical and physical characteristics, they carry different part numbers and are not listed interchangeably in these specifications.
• The 1891 bulb is specified for the Chevrolet Brookwood across the 1958-1961 model years, making it the most consistently used radio display bulb across the widest span of years in this dataset.
• The 1893 bulb applies to the 1969-1971 model years. Because the 1893 and 1891 share the same T5 form factor and 12V/2W rating, any substitution between them should be verified against manufacturer fitment data before use, as these specifications treat them as separate entries.
• The 1816 is the only bulb in these specifications that uses a T3.25 envelope rather than a T5. It is rated at 12V and 4W, making it the highest-wattage bulb listed, and it applies exclusively to the 1972 model year.
• The T3.25 envelope of the 1816 is physically smaller than the T5 envelope used by the 1891 and 1893. This size difference means the 1816 is not a drop-in substitute for the bulbs used in earlier Brookwood model years.
• All three bulb types conform to ANSI standards recognized in both the United States and Canada, indicating standardized production tolerances and base compatibility within their respective designations.
• The shift from a 2W bulb in 1971 to a 4W bulb in 1972 represents a doubling of wattage for the radio display circuit, which may reflect a change in the display design or illumination requirements for that model year.