Ford Falcon Map Light Bulb Size

Additional Notes

• The Ford Falcon uses the 631 bulb as the map light specification across the majority of its model years covered, specifically 1962 and 1964-1970.
• The 631 is an ANSI-standardized bulb rated at 12 volts and 21 watts, making it a relatively high-output incandescent for an interior map light application.
• It uses a BA15s bayonet base, which is a single-contact bayonet fitting. This base type requires a twist-and-lock installation rather than a simple push-in socket.
• The 631 is a single-filament bulb and a variant of the more widely known 1156, meaning the two share design lineage, though they are not necessarily interchangeable without confirming voltage and wattage tolerances for a given socket.
• The 1963 Ford Falcon map light departs from the 631 specification, instead calling for the 1895 bulb, which represents a significantly different component in both construction and output.
• The 1895 is a T5 miniature wedge bulb rated at 12 volts and 0.9 watts, a fraction of the wattage of the 631. Its wedge base is inserted directly into a friction-fit socket with no bayonet mechanism involved.
• Because the 631 and 1895 use physically incompatible base types, a BA15s bayonet socket and a wedge socket are not interchangeable, and the 1963 model year requires a distinct socket configuration from the surrounding years.
• Both the 631 and 1895 are governed by ANSI standards applicable to the United States and Canada, meaning their specifications conform to a defined industry classification system rather than proprietary manufacturer sizing.