Austin Marina Back Up Light Bulb Size

The Austin Marina back up light requires bulb size 1156 or P21W depending on the specific vehicle configuration. Data for the bulb sizes covers the range from 1973 to 1975.

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
1973-1975	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 Austin Marina backup light across the 1973-1975 model years.
The 1156 is an ANSI-standardized bulb used in the United States and Canada, operating at 12 volts with a 21-watt output.
As a single-filament bulb, the 1156 serves functions requiring only one circuit, which aligns with the dedicated on/off nature of a backup light.
The 1156 uses a BA15s bayonet base, a single-contact fitting where the "s" denotes a single pin, distinguishing it from the dual-contact BA15d variant with which it is not interchangeable.