Audi S5 Dome Light Bulb Size

The Audi S5 dome light utilizes 6411 and DE3423 bulb sizes for the interior illumination system. Data for the specified components covers the range from 2008 through 2018.

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
2013-2018	6411
2008-2012	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 Audi S5 dome light specifications cover model years 2008-2018 and reference two festoon bulb types: the 6411 and the DE3423.
A festoon bulb is a cylindrical lamp that mounts horizontally between two contact points at either end of a housing, a form factor common in automotive interior lighting.
The 6411 bulb is specified for the Audi S5 across model years 2013-2018. It is an ANSI-standard festoon type with a 36mm length, an SV8.5 base, and a 12V, 5W electrical rating.
The SV8.5 base on the 6411 uses a center-pin contact on each end cap, which is a distinct mounting interface from simple flat end-cap contacts.
The DE3423 bulb is specified for the Audi S5 across model years 2008-2012. It is also an ANSI-standard festoon type, rated at 12V, with a 41mm length and flat end-cap contacts.
The 6411 and DE3423 are not interchangeable. Beyond the difference in base contact design, the 6411 measures 36mm while the DE3423 measures 41mm, meaning neither will seat correctly in a housing designed for the other.
Both bulb types carry ANSI standardization applicable to the US and Canadian markets, indicating the specifications reflect North American vehicle configurations.
The transition between bulb types occurs between the 2012 and 2013 model years of the Audi S5, where the dome light housing changed from accommodating the 41mm DE3423 to the 36mm 6411.