Jaguar XF Back Up Light Bulb Size

Additional Notes

• The Jaguar XF back up light specifications reference two distinct bulb types across the model's production years: the 921 and the 5201, both of which conform to ANSI standards recognized in the United States and Canada.
• The 921 is a T15 wedge-base bulb operating at 12 volts and 16 watts. The wedge base design means the bulb is held in place by tension from the socket itself rather than by a separate locking mechanism.
• The 5201 is a single-filament halogen bulb fitted with a PG20-1 base, operating at 12 volts and 19 watts. The PG20-1 is a plastic-base connector type, and its physical base configuration is not interchangeable with the wedge socket used by the 921.
• The Jaguar XF (2016-2024) uses the 921 bulb for the back up light position, while the 2009-2015 model years use the 5201.
• The 921 and 5201 differ in both base type and wattage, making them incompatible with each other's sockets. Substituting one for the other without an appropriate adapter is not supported by the specifications.
• The 5201 draws 19 watts compared to the 921's 16 watts. Installing a higher-wattage bulb in a socket rated for a lower wattage can place excess thermal and electrical load on the housing and circuit.
• Both bulb types operate on a 12-volt electrical system, which is standard for passenger vehicle lighting circuits.
• The shift from the 5201 to the 921 between the 2015 and 2016 XF model years reflects a change in socket and housing design, meaning components from one generation's tail lamp assembly are not directly transferable to the other.