Jaguar XJ12 License Plate Bulb Size

The Jaguar XJ12 license plate light requires a DE3423 bulb size for proper installation and function within the rear exterior lighting assembly. Available data for the specified bulb covers the period from 1973 through 1996.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1994-1996	DE3423
1973-1979	DE3423

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 41mm length, end-cap contacts. 12V.	DE3423

Other Locations

Additional Notes

The Jaguar XJ12 uses the DE3423 bulb across all listed model years for the license plate position.
The DE3423 is a festoon-type bulb, meaning it is cylindrical in form and makes electrical contact through metal caps at each end rather than through a base socket.
The DE3423 operates at 12 volts, which is consistent with standard automotive electrical systems.
At 41mm in length, the DE3423 fits within a festoon holder designed for that specific span between contact points, making fitment sensitive to length.
The DE3423 carries ANSI designation, indicating it meets standardized specifications recognized in the United States and Canada.
The Jaguar XJ12 used the DE3423 for the license plate position across the 1973-1979 and 1994-1996 model years as listed in the specifications.
Because festoon bulbs rely on end-cap contact rather than a keyed base, substituting a festoon bulb of a different length risks poor contact or failure to seat within the housing.