Lamborghini Diablo Back Up Light Bulb Size

The Lamborghini Diablo back up light utilizes a P21W bulb size for illumination purposes. Available data covers a specific range from 1990 through 2001 for the specified vehicle components.

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
1990-2001	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 Lamborghini Diablo uses the P21W bulb for its back up light across the full 1990-2001 model range.
The P21W is an ECE-standard bulb, meaning it conforms to the Economic Commission for Europe regulatory framework widely adopted across European and international automotive markets.
As a single-filament bulb, the P21W is designed exclusively for on/off signalling functions rather than variable-intensity applications, which aligns with its role as a back up light.
The P21W operates at 12 volts and draws 21 watts, placing it in the standard signalling power range for incandescent automotive bulbs.
The bulb 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, consistent with its single-filament design.
The BA15s base is distinct from the BA15d (dual-contact) base; substituting a dual-contact bulb in a single-contact socket is not compatible, and the two types are not interchangeable despite sharing the same 15mm bayonet collar width.