Audi A4 License Plate Bulb Size

The Audi A4 license plate light requires a DE3423 bulb size for proper installation and function within the rear exterior lighting assembly. Provided data covers a span of time starting from 1996 through 2012.

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
2007-2012	DE3423
1999-2002	DE3423
1996-1997	DE3423

Bulb Specifications

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

Other Locations

Additional Notes

The Audi A4 uses the DE3423 bulb for the license plate position across all listed model years from 1996-2012.
The DE3423 is a festoon-type bulb, meaning it is cylindrical in shape and makes electrical contact through metal caps at each end rather than through a base socket or pins.
The DE3423 operates at 12 volts, which is consistent with the standard electrical system voltage found in passenger vehicles.
The bulb has a 41mm length, which is the critical fitment factor for festoon bulbs, as the end caps must span the contact points within the housing correctly.
The DE3423 designation follows ANSI standards applicable in the United States and Canada, meaning it conforms to a defined set of dimensional and electrical performance criteria within those markets.
Because festoon bulbs rely on length for proper contact, substituting a festoon bulb of a different length, such as a 36mm or 44mm unit, would result in a poor or failed connection even if the voltage rating matches.