Jaguar XK8 Back Up Light Bulb Size

The Jaguar XK8 back up light utilizes a P21W bulb size for the rear illumination system. Available data covers the production span from 1997 through 2006 for the specified vehicle.

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
1997-2006	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 Jaguar XK8 uses the P21W bulb for the back up light position across all listed model years from 1997-2006.
The P21W is an ECE-regulated bulb type, meaning it conforms to European and internationally recognized standards for automotive lighting.
P21W bulbs operate on a 12-volt electrical system and draw 21 watts, which is typical for single-filament signalling applications.
The P21W uses a BA15s bayonet base, which is a single-contact bayonet fitting with a 15mm collar width.
Because the P21W is a single-filament bulb, it serves one lighting function only, distinguishing it from dual-filament variants such as the P21/5W, which would not be a compatible substitute.
The BA15s base designation indicates a single offset pin, and substituting a bulb with a BA15d base (dual pin) would result in an incompatible fit despite the similar physical appearance of the two base types.
The P21W designation is an ECE type reference rather than a North American ANSI/SAE trade number, so cross-referencing may be necessary when sourcing replacements in markets where ECE nomenclature is less common.