Ford Ranchero Back Up Light Bulb Size

The Ford Ranchero back up light utilizes 1141, 1156, and P21W bulb sizes for illumination. Available information covers the span of time from 1958 through 1979.

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
1960-1979	1156
1959	1141
1958	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1141

Other Locations

Additional Notes

The Ford Ranchero back up light specifications cover model years 1958-1979, with the 1156 bulb specified for all years except 1959.
The 1156 is an ANSI-standard single-filament bulb rated at 12 volts and 21 watts, fitted with a BA15s bayonet base.
The 1141 bulb, specified for the 1959 Ford Ranchero, shares the same ANSI-standard single-filament design, BA15s bayonet base, 12-volt rating, and 21-watt output as the 1156.
Despite their near-identical electrical and mechanical specifications, the 1156 and 1141 are distinct part numbers and are not listed as interchangeable within these specifications.
The BA15s bayonet base is a single-contact fitting, which is consistent with the single-filament design of both bulb types listed here, as a single-filament back up light requires only one electrical contact.
The 21-watt output rating on a 12-volt system places both bulb types in a range typical of automotive back up lighting, providing sufficient illumination for reversing without the higher wattage associated with headlamp applications.
Both the 1156 and 1141 carry ANSI designations valid in the United States and Canada, reflecting standardized dimensional and electrical tolerances across manufacturers producing these bulb types.