Oldsmobile 442 Back Up Light Bulb Size

The Oldsmobile 442 back up light requires 1156 and P21W bulb sizes for the exterior lighting system. Data for the specific components covers the range from 1964 to 1971.

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
1964-1971	1156

Bulb Specifications

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

Other Locations

Additional Notes

The Oldsmobile 442 uses the 1156 bulb across all listed model years, spanning 1964-1971, for the back up light position.
The 1156 is a single-filament bulb, meaning it serves one lighting function only, which is consistent with its application in a dedicated back up light circuit.
The 1156 operates at 12 volts and 21 watts, placing it in the standard range for incandescent automotive reverse lighting of that era.
The 1156 uses a BA15s bayonet base, a single-contact bayonet mount with a 15mm collar width, which requires a matching socket in the vehicle's lamp housing.
The 1156 is an ANSI-standardized bulb recognized in both the United States and Canada, meaning the specification applies uniformly across North American market vehicles.
Because the 1156 is single-filament, it is not interchangeable with the physically similar 1157 bulb, which carries a dual-filament design and a different base pin configuration despite sharing the same BA15 bayonet family.