Land Rover Discovery Dome Light Bulb Size

The Land Rover Discovery dome light uses bulb sizes DE3423 and 6461 depending on the specific version of the vehicle. Available data for the components covers the range from 1994 to 2004.

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
2003-2004	DE3423
1994-2002	6461

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 41mm length, end-cap contacts. 12V.	DE3423
ANSI standard (US & Canada). Festoon bulb, 36mm length, SV8.5 base. 12V, 5W.	6461

Other Locations

Additional Notes

The Land Rover Discovery uses two festoon bulb types across its dome light specifications: the DE3423 and the 6461. Both conform to ANSI standards applicable in the United States and Canada, and both operate at 12 volts.
The 6461 bulb is the dominant fitment across the Land Rover Discovery lineup, covering model years 1994-2002.
The 6461 is a 36mm festoon bulb with an SV8.5 base and a rated output of 5 watts. The SV8.5 designation refers to a bayonet-style festoon base with a nominal 8.5mm cap width, which is a common automotive interior lighting format.
The DE3423 applies to the 2003-2004 Land Rover Discovery. It is a 41mm festoon bulb with end-cap contacts, which differ structurally from the SV8.5 base found on the 6461.
The DE3423 and 6461 are not interchangeable. Although both are 12-volt festoon bulbs, the DE3423 is 41mm in length with end-cap contacts, while the 6461 is 36mm with an SV8.5 base. The difference in both physical length and contact type makes cross-substitution incompatible.
Festoon bulbs are cylindrical lamps that make contact at both ends rather than through a side-mounted base. This form factor is standard in automotive dome and interior lighting applications.
The transition from the 6461 to the DE3423 occurred between the 2002 and 2003 model years, representing a change in both bulb length and contact configuration for the dome light position.