Oldsmobile Fiesta Back Up Light Bulb Size

The Oldsmobile Fiesta back up light utilizes 1073 and P21W bulb sizes for the specific lighting components. Available data for the specified vehicle covers the period from 1953 to 1964.

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
1958-1964	P21W
1957	1073
1953	1073

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. Lower wattage variant of 1156. 12V, 13W.	1073

Other Locations

Additional Notes

The Oldsmobile Fiesta back up light specifications cover model years 1953-1964, with two distinct bulb types used across that span.
The P21W is an ECE-standard single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base and used in European and worldwide automotive applications.
The 1073 is an ANSI-standard single-filament bulb rated at 12V and 13W, also fitted with a BA15s bayonet base, and is classified as a lower wattage variant of the 1156 bulb.
The P21W is specified for the Oldsmobile Fiesta across model years 1958-1964, making it the more widely applied of the two bulb types in these specifications.
The 1073 is specified for the 1957 and 1953 model years.
Although both the P21W and the 1073 share a BA15s bayonet base, they are not interchangeable due to their differing wattage ratings of 21W and 13W respectively.
Substituting a P21W in place of a 1073 would introduce a higher wattage draw than the original circuit was specified to accommodate in the 1953 and 1957 models.