Volvo 740 Back Up Light Bulb Size

The Volvo 740 back up light uses a P21W bulb size for the reverse lighting assembly. The replacement chart covers 1985 to 1992 production years with corresponding bulb specifications.

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
1985-1992	P21W

Bulb Specifications

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

Other Locations

Additional Notes

The P21W is the sole back up light bulb type listed across all model years of the Volvo 740, covering 1985-1992.
The P21W follows the ECE (Economic Commission for Europe) standard, a regulatory framework adopted across Europe and numerous other markets worldwide.
As a single-filament bulb, the P21W is dedicated to one lighting function, which in this application is the reverse light.
The P21W operates at 12 volts and draws 21 watts, placing it in the mid-range of automotive signalling bulb wattages.
The P21W uses a BA15s bayonet base, where "BA" denotes a bayonet cap fitting, "15" refers to the 15mm base width, and "s" indicates a single contact at the base.
The BA15s single-contact base is distinct from the BA15d double-contact variant; the two are not interchangeable despite sharing the same physical base width.