Jaguar XJ12 Dome Light Bulb Size

The Jaguar XJ12 dome light requires bulb size 6411 or DE3423 depending on the specific version of the vehicle. Data for the lighting components covers the range from 1973 to 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	6411
1978-1979	6411
1973-1977	DE3423

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 36mm length, SV8.5 base. 12V, 5W.	6411
ANSI standard (US & Canada). Festoon bulb, 41mm length, end-cap contacts. 12V.	DE3423

Other Locations

Additional Notes

The Jaguar XJ12 dome light uses two bulb types across its model years: the 6411 and the DE3423, both festoon-style bulbs operating on a 12-volt system.
Festoon bulbs are cylindrical lamps that make electrical contact at both ends of the housing rather than through a side-mounted base pin, a design common in interior automotive lighting applications.
The 6411 is specified for the 1994-1996 and 1978-1979 model years of the Jaguar XJ12 dome light position.
The 6411 bulb carries an SV8.5 base designation, meaning it uses a single-contact end-cap with an 8.5mm cap width, and is rated at 12V and 5W with a 36mm length.
The DE3423 is specified for the 1973-1977 model years in the dome light position.
The DE3423 measures 41mm in length, making it physically longer than the 6411, and uses end-cap contacts without an SV8.5 base classification.
Because the 6411 and DE3423 differ in length by 5mm, the two bulb types are not interchangeable despite both being festoon-style 12-volt lamps.
Both the 6411 and DE3423 conform to ANSI standards applicable to the US and Canadian markets.