Audi A5 Dome Light Bulb Size

The Audi A5 dome light requires 6411 and DE3423 bulb sizes for the interior lighting system. Data for the provided specifications covers the range from 2010 to 2014.

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
2013-2014	6411
2010-2012	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 A5 dome light uses two festoon bulb types across the 2010-2014 model years: 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 interior automotive lighting.
The 6411 bulb is specified for the 2013-2014 Audi A5. It operates at 12V, 5W, measures 36mm in length, and uses an SV8.5 base.
The SV8.5 base on the 6411 means the bulb makes contact through a metal cap on each end, sized to fit an 8.5mm-wide festoon socket.
The DE3423 bulb is specified for the 2010-2012 Audi A5. It also operates at 12V and uses a festoon form factor, but at 41mm in length with end-cap contacts.
The 6411 and DE3423 are not interchangeable. The 5mm difference in length between the two bulbs means each is sized for a distinct housing, and substituting one for the other risks a poor fit or no contact.
Both bulb types conform to ANSI standards applicable in the United States and Canada, indicating standardized electrical and physical tolerances within those markets.
The DE3423 does not carry a wattage value in the specifications, whereas the 6411 is rated at 5W.