Maserati Biturbo Back Up Light Bulb Size

The Maserati Biturbo back up light utilizes P21W and 1156 bulb sizes for the rear illumination components. Data for the specified lighting equipment covers the range from 1983 through 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
1983-1987	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 1156 is an ANSI-standardized bulb used in the United States and Canada, operating at 12 volts with a 21-watt output.
The 1156 uses a single-filament design, which is standard for backup light applications where only one consistent light output level is required.
The BA15s bayonet base on the 1156 features a single locating pin, distinguishing it from the BA15d double-pin base found on dual-filament variants such as the 1157.
The Maserati Biturbo used the 1156 bulb for its backup lights across the 1983-1987 model years.
Because the BA15s base is single-pin, it is not interchangeable with dual-pin bayonet bulbs, even when the physical housing size is similar.
The single-filament construction of the 1156 means it cannot serve as a direct replacement in sockets designed for dual-filament bulbs without a wiring or socket modification.
At 21 watts, the 1156 falls within the standard wattage range for incandescent backup lights, reflecting typical thermal and electrical load expectations for the vehicle's original circuit design.