Nissan 610 Back Up Light Bulb Size

The Nissan 610 back up light requires a P21W bulb size for proper installation and function within the rear lighting assembly. Data for the specified component covers the range from 1973 to 1976.

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
1973-1976	P21W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W

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Additional Notes

The P21W is the sole bulb type listed across all recorded model years of the Nissan 610, covering the 1973-1976 back up light positions.
The P21W operates on a 12-volt electrical system and draws 21 watts, which is the standard power rating for single-filament signalling applications in automotive use.
As a single-filament bulb, the P21W is dedicated to one function at a time, making it appropriate for a back up light that operates independently rather than sharing a circuit with another lighting function.
The P21W uses a BA15s bayonet base, where "BA" denotes a bayonet cap fitting, "15" refers to the 15mm base width, and the lowercase "s" indicates a single contact at the base, corresponding to its single-filament construction.
The P21W is governed by ECE regulations, a lighting standard recognized across Europe and numerous other markets worldwide, which defines its electrical and photometric performance requirements.
The BA15s base of the P21W is not interchangeable with the BA15d base, which carries two contacts for dual-filament bulbs. Substituting one for the other is not physically compatible despite the shared 15mm base width.