Mercury Park Lane Dome Light Bulb Size

The Mercury Park Lane dome light utilizes 1003 and 1816 bulb sizes for interior illumination. Data for the specific lighting components spans from 1958 through 1968.

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
1968	1003
1967	1816
1964-1966	1003
1958-1960	1003

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1003
ANSI standard (US & Canada). Miniature wedge bulb (T3.25). 12V, 4W.	1816

Other Locations

Additional Notes

The 1003 bulb is the dominant dome light specification across the Mercury Park Lane, appearing in the 1958-1960 and 1964-1966 model years, as well as 1968.
The 1003 is a single-filament bulb rated at 12 volts and 21 watts, fitted with a BA15s bayonet base, which is a single-contact bayonet mount with a 15mm base width.
The BA15s bayonet base requires a twist-and-lock installation, where the bulb is pressed into the socket and rotated to secure it in place.
The 1816 bulb was specified exclusively for the 1967 Mercury Park Lane, making that model year distinct from all others in this range.
The 1816 is a miniature wedge bulb of the T3.25 type, rated at 12 volts and 4 watts, which represents a substantially lower wattage output than the 1003.
A T3.25 wedge bulb uses no base hardware; the glass envelope itself acts as the retaining element within the socket, making it physically incompatible with a BA15s bayonet socket.
The 1003 and 1816 are not interchangeable. The difference in base type, wattage, and physical form means substituting one for the other is not supported by these specifications.
Both bulb types conform to ANSI standards applicable in the United States and Canada, indicating standardized electrical and physical tolerances within those markets.