INFINITI G20 Back Up Light Bulb Size

The INFINITI G20 back up light utilizes 921, P21W, and 1156 bulb sizes depending on the specific version of the vehicle. Available data for the components covers the range from 1991 to 2002.

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
1999-2002	921
1991-1996	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

Other Locations

Additional Notes

The INFINITI G20 backup light specifications cover model years 1991-2002, with two distinct bulb sizes used across that span depending on the production era.
The 921 bulb is specified for the G20 across the 1999-2002 model years. It is a T15 wedge-base bulb rated at 12V and 16W, conforming to ANSI standards for the US and Canadian markets.
The 1156 bulb is specified for the 1991-1996 model years. It is a single-filament bulb with a BA15s bayonet base, rated at 12V and 21W, also conforming to ANSI standards for the US and Canadian markets.
The two bulb types are not interchangeable. The 921 uses a wedge base, while the 1156 uses a BA15s bayonet base, meaning the socket design differs between the two production generations of the G20.
The 1156 bulb draws 21W compared to the 921's 16W, reflecting a difference in power consumption between the two generations of the G20's backup light system.
The BA15s designation on the 1156 bulb indicates a single-contact bayonet base with a 15mm collar, a base type commonly found in single-filament automotive applications such as turn signals and reverse lights.
The T15 designation on the 921 bulb refers to the bulb's tubular shape, sized at 15/8 of an inch in width, a form factor widely used in modern automotive backup and interior lighting.
Both bulb types are rated at 12V, consistent with the standard electrical system voltage found in passenger vehicles of these model years.