The Jaguar XK8 turn signal requires a PY21W bulb size for proper installation and function within the lighting assembly. Data for the specified component covers the period from 1997 through 2006.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The two bulb types specified across all turn signal positions on the Jaguar XK8 are the 12496 and the PY21W. Both operate at 12 volts, making them electrically compatible with the vehicle's standard automotive electrical system.
The 12496 is a halogen bulb designated under a Philips/Osram part numbering system, classified as a specialty application bulb. It is rated at 12V.
The PY21W is defined under ECE (Economic Commission for Europe) standards and is widely used in European and international automotive markets. It is a single-filament amber bulb rated at 12V and 21W, fitted with a BAU15s bayonet base.
The BAU15s base on the PY21W features offset pins, which physically prevent it from being seated in sockets designed for other bayonet-style bases such as the BA15s. This offset is a deliberate design feature to avoid incorrect bulb installation.
The front turn signal position on the Jaguar XK8 does not use a single bulb type across all model years. The 12496 is specified for 1997-2000, 2003, and 2006, while the PY21W is specified for 2001-2002 and 2004-2005.
The rear turn signal position similarly alternates between the two bulb types across model years, with the 12496 specified for 1997-1998, 2000-2001, 2006, and the PY21W specified for 1999 and 2002-2005.
In several model years, the front and rear turn signal positions on the XK8 do not share the same bulb type. For example, in 2003 the front position calls for a 12496 while the rear position calls for a PY21W.
Because the 12496 and PY21W differ in base type and physical construction, they are not interchangeable. Installing the incorrect bulb type for a given model year and position risks improper fitment or failure to seat correctly in the socket.
The amber color of the PY21W is built into the glass envelope of the bulb itself, rather than produced by a colored lens. This is a characteristic of bulbs meeting ECE amber turn signal requirements.
The alternating specification pattern across model years indicates that the XK8 underwent component changes during its production run that affected socket compatibility at both the front and rear turn signal positions.