American Motors Spirit Back Up Light Bulb Size

The American Motors Spirit back up light utilizes 1156 and P21W bulb sizes for illumination. Data for the specified lighting components covers the period from 1979 through 1983.

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
1979-1983	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 American Motors Spirit uses the 1156 bulb for the back up light across all listed model years, 1979-1983.
The 1156 is an ANSI-standardized bulb type, meaning its physical and electrical specifications are governed by a recognized North American standard shared across the US and Canada.
The 1156 operates on a 12-volt electrical system and draws 21 watts, which is consistent with standard automotive reverse lighting 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 simultaneously.
The 1156 uses a BA15s bayonet base, where "BA15s" denotes a bayonet fitting with a 15mm collar and a single contact pin, which locks the bulb into the socket with a push-and-twist motion.
Because the BA15s base has a single offset pin, it is not interchangeable with the BA15d base, which carries two pins and is found on dual-filament bulbs such as the 1157.