Mazda RX-2 Back Up Light Bulb Size

The Mazda RX-2 back up light requires a unique 1156 bulb size for the lighting assembly. Data for the specific component covers the range from 1973 to 1974.

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
1973-1974	1156

Bulb Specifications

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

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Additional Notes

The 1156 is the sole bulb type specified for the Mazda RX-2 backup light across both listed model years, 1973-1974.
The 1156 is an ANSI-standardized bulb recognized in the United States and Canada, meaning it conforms to a defined set of electrical and physical parameters shared across compliant manufacturers.
The 1156 operates on a 12-volt electrical system and draws 21 watts, which is consistent with standard automotive incandescent backup light applications of that era.
The bulb uses a BA15s bayonet base, a single-contact fitting where the "s" designation indicates a single pin positioned symmetrically on the base, allowing only one correct seating orientation in terms of pin alignment.
The 1156 is a single-filament bulb, meaning it serves one lighting function only, as opposed to dual-filament types that combine two functions such as braking and running light within one unit.
Because the BA15s base is a widely used standard, the 1156 is physically interchangeable with other bulbs sharing that base type, though wattage and voltage ratings of any substitute would need to match to avoid electrical or fitment issues.