Subaru XT Back Up Light Bulb Size

The Subaru XT back up light utilizes 1156 and P21W bulb sizes for illumination purposes across various production versions. Data for the specified lighting components covers the period from 1985 through 1991.

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
1985-1991	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 1156 is the sole back up light bulb size listed for the Subaru XT across all model years covered in the specifications.
The Subaru XT used the 1156 bulb for its back up lights from 1985-1991, representing the full span of years in the specifications.
The 1156 is an ANSI-standardized bulb type, meaning its physical and electrical characteristics conform to a defined industry standard recognized in both the United States 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 such as the 1157, which handle two functions from a single housing.
The 1156 uses a BA15s bayonet base, a single-contact mount where the bulb is inserted and rotated to lock into place. The "s" in BA15s denotes a single contact point at the base, distinguishing it from the BA15d, which has two contacts and is not interchangeable.