The Jaguar Super V8 brake light requires P21W and P21/5W bulb sizes for the rear lighting system. Data for the specified components covers the range from 2005 to 2009.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Jaguar Super V8 brake light circuit uses two distinct bulb types across its production run: the single-filament P21W for 2007-2009 models and the dual-filament P21/5W for 2005-2006 models.
The P21W follows the ECE lighting standard and operates on a BA15s bayonet base, a single-contact fitting that physically prevents installation of a dual-filament bulb in the same socket.
The P21/5W also follows the ECE standard but uses a BAY15d bayonet base, which features offset pins to ensure correct polarity orientation. Both filaments operate at 12V, with the primary filament rated at 21W and the secondary at 5W.
Because the BA15s and BAY15d bases are mechanically different, P21W and P21/5W bulbs are not interchangeable, even though both operate at 12V and share the same primary wattage rating.
The Jaguar Super V8 (2005-2006) uses a dual-filament P21/5W for the brake light, meaning the same bulb serves two functions within the circuit, typically combining stop and tail light duties in a single unit.
The center high mount stop light on the Jaguar Super V8 uses the 12961, a Philips-designated T10 wedge bulb with a W2.1x9.5d base, rated at 12V and 5W across the 2005-2008 model years.
The T10 wedge format of the 12961 relies on the flexibility of its base contacts rather than a locking bayonet mechanism, making socket condition a relevant factor in maintaining a reliable electrical connection.
At 5W, the 12961 operates at a significantly lower wattage than the P21W and P21/5W brake bulbs, which is consistent with its role in a high-mount stop light rather than a primary brake light assembly.
The 2009 model year carries a P21W specification for the brake light but has no corresponding center high mount stop light entry in the specifications, while 2005-2008 models have documented fitment for that position.