Jaguar XJS Dome Light Bulb Size

The Jaguar XJS dome light utilizes 6411 and DE3423 bulb sizes for interior illumination across various production versions. Available data spans a range from 1976 through 1996 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.

Bulb Size by Year Range

Years	Bulb Size
1980-1996	6411
1976-1979	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 XJS dome light uses two distinct bulb sizes across its production span, with the 6411 fitted to the 1980-1996 models and the DE3423 fitted to the 1976-1979 models.
Both the 6411 and DE3423 are festoon-type bulbs, meaning they are cylindrical in shape and mount horizontally between two contact points within the dome light housing.
The 6411 is rated at 12 volts and 5 watts, operating on the standard automotive electrical system voltage common to most passenger vehicles of this era.
The 6411 uses an SV8.5 base, which refers to a single-contact festoon base with a body width of 8.5mm, where the bulb makes contact through its end caps seated in spring-loaded holders.
The DE3423 is also rated at 12 volts and uses end-cap contacts, though no wattage figure is specified for this bulb in the provided data.
The 6411 has a 36mm length, while the DE3423 is 41mm long, making the two bulbs physically incompatible with each other despite both being festoon types.
Both bulb sizes conform to ANSI standards applicable to the United States and Canada, indicating they follow a standardized specification recognized across North American markets.
The difference in festoon length between the two bulbs is a critical fitment factor, as installing a 36mm bulb into a housing designed for a 41mm festoon, or vice versa, would result in poor contact or failure to seat properly.