Mercury Park Lane Back Up Light Bulb Size

The Mercury Park Lane back up light uses bulb size 1141 and bulb size P21W for illumination. Available data for the specific bulb sizes covers the range from 1958 to 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	P21W
1964-1967	1141
1958-1960	P21W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1141

Other Locations

Additional Notes

The backup light bulbs specified for the Mercury Park Lane across all listed model years fall into two types: the P21W and the 1141. Both share identical electrical ratings of 12V and 21W, and both use a BA15s single-contact bayonet base with a single filament.
Despite their shared physical and electrical characteristics, the P21W follows the ECE standard used in Europe and worldwide markets, while the 1141 follows the ANSI standard used in the United States and Canada.
The Mercury Park Lane used the 1141 bulb for the 1964-1967 model years, making it the more frequently specified type across the listed entries.
The P21W was specified for the 1958-1960 and 1968 model years.
Because the P21W and 1141 share the same BA15s bayonet base and the same 12V, 21W rating, the two types are electrically and physically interchangeable in practice, though they originate from different regional standards bodies.
The BA15s base designation indicates a single-contact bayonet fitting with a 15mm base width, which is a widely used base type in automotive signalling applications.