Pontiac G3 Back Up Light Bulb Size

The Pontiac G3 back up light requires bulb size 1156 or P21W depending on the specific version of the vehicle. Data for the lighting components covers the range from 2009 to 2010.

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
2009-2010	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 bulb type listed for the Pontiac G3 backup light across both available model years, 2009-2010.
The 1156 operates at 12 volts with a 21-watt single-filament design, making it a standard incandescent bulb suited for on/off lighting functions such as backup lights.
The 1156 uses a BA15s bayonet base, a single-contact fitting where the "s" denotes a single pin offset on the base collar, distinguishing it from double-contact variants.
The 1156 is classified under the ANSI standard, meaning its electrical and physical specifications are standardized for the United States and Canada markets.
Because the 1156 is a single-filament bulb, it serves one lighting function per socket, which aligns with the dedicated role of a backup light circuit.
The BA15s bayonet base of the 1156 is not interchangeable with the BA15d base used on dual-filament bulbs, as the pin configuration differs between the two types.