Subaru Standard Back Up Light Bulb Size

The Subaru Standard back up light utilizes 1156 and P21W bulb sizes for illumination across various production periods. Available data for the specified vehicle covers the range from 1979 to 1987.

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
1979-1987	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 Subaru Standard uses the 1156 bulb for the back up light across all listed model years, spanning 1979-1987.
The 1156 is an ANSI-standardized bulb type, meaning its physical and electrical specifications are governed by a recognized North American standard applicable in both the US and Canada.
The 1156 operates on a 12-volt electrical system and draws 21 watts, which is consistent with standard automotive incandescent back up light applications.
The 1156 is a single-filament bulb, meaning it serves one lighting function only, as opposed to dual-filament types that handle two functions such as braking and running light from a single unit.
The 1156 uses a BA15s bayonet base, where "BA15s" denotes a single-contact bayonet fitting with a 15mm base width, a common base type in automotive lighting.
The BA15s base requires a twist-lock installation rather than a screw-in method, which is a fitment detail relevant when sourcing a replacement bulb for the Subaru Standard.
The 1156 should not be substituted with the visually similar 1157, as the 1157 is a dual-filament bulb with a BA15d double-contact base, making it electrically and physically incompatible with a single-contact socket.