The Jaguar XKR brake light uses a P21/5W bulb size for the rear lighting system. Available data covers the range from 2000 to 2015 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.
The Jaguar XKR uses the P21/5W bulb for brake lighting across the 2000-2015 model years, making it the dominant bulb type in these specifications.
The P21/5W is an ECE-standard dual-filament bulb rated at 12V with a 21W brake filament and a 5W running filament, mounted on a BAY15d bayonet base.
The BAY15d base features offset pins, which physically prevents incorrect single-filament bulbs from being seated in the socket, as the pin positions are not symmetrical.
The center high mount stop light on the Jaguar XKR uses the 12961 bulb for the 2000-2006 model years.
The 12961 is a Philips part number designating a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12V and 5W.
The T10 wedge format of the 12961 is a single-filament design, which is consistent with its application in a dedicated stop light position rather than a combined stop and tail function.
The P21/5W and 12961 are not interchangeable, as they differ in base type, filament count, wattage, and physical form factor.
The BAY15d bayonet base of the P21/5W and the W2.1x9.5d wedge base of the 12961 are mechanically incompatible with each other's sockets.