Jaguar XK8 front fog light bulbs utilize H1 and H3 sizes, while rear fog light bulbs use P21W size. The replacement chart covers 1997 to 2006 model production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Jaguar XK8 front fog light uses the H1 bulb for the 1998-2006 model years, while the 1997 model year uses the H3 bulb instead.
Both the H1 and H3 are single-filament halogen bulbs operating at 12V and 55W, meaning they share identical power consumption despite being physically different and non-interchangeable.
The H1 bulb uses a P14.5s base, whereas the H3 uses a PK22s base. These two base types are incompatible with each other, so the 1997 front fog housing does not accept the H1 used in later model years.
Both H1 and H3 bulbs carry ECE certification and are also approved for use in the United States and Japan, reflecting their broad regulatory acceptance across major automotive markets.
The rear fog light on the Jaguar XK8 uses the P21W bulb across the 1997-2002 model years.
The P21W is a single-filament signalling bulb rated at 12V and 21W, which is a notably lower wattage than the halogen fog bulbs used at the front, reflecting its role as a signalling rather than an illumination lamp.
The P21W uses a BA15s bayonet base, a fitting type that is mechanically distinct from the pin-style bases of both the H1 and H3, making cross-substitution between front and rear fog bulbs impossible.
Like the H1 and H3, the P21W is an ECE-standard bulb with approval across European and worldwide markets.