Oldsmobile F85 Dome Light Bulb Size

Additional Notes

• The 211-2 is a festoon-type bulb measuring 41mm in length with an SV8.5 base, operating at 12V and 12W. Festoon bulbs seat by pressing lengthwise between two spring-loaded contacts rather than inserting into a socket.
• The Oldsmobile F85 dome light uses the 211-2 bulb across the majority of its model years, specifically 1961 and 1963-1972, with the exception of 1962 and 1971.
• The 161 is a T10 miniature wedge bulb rated at 12V and 1W, which is substantially lower wattage than the 211-2. The F85 uses this bulb exclusively for the 1971 dome light.
• The 1962 F85 dome light uses the 1004 bulb, which features a BAY15d bayonet base and a dual-filament design rated at 12V and 21/5W. The BAY15d base has two pins offset at different heights to ensure correct orientation during installation.
• The 1004 is noted as a variant of the 1157, a widely used automotive bulb. Despite this relationship, the two are not confirmed as interchangeable within these specifications, and substitution should be approached with caution.
• All three bulb types in these specifications conform to ANSI standards applicable in the United States and Canada, meaning they share a common regulatory framework for electrical and physical tolerances.
• The 211-2, 161, and 1004 each use a different base type: SV8.5 festoon, wedge, and BAY15d bayonet, respectively. These base types are physically incompatible with one another, so no cross-year substitution is possible without a socket adapter or fixture modification.
• The wattage difference between the 1971 dome bulb (161 at 1W) and the surrounding model years (211-2 at 12W) is significant. A direct swap between these two types would not be appropriate given the difference in both base design and power draw.