Audi RS4 License Plate Bulb Size

The Audi RS4 license plate light requires a unique DE3423 bulb size for proper installation and function. Data for the specific bulb requirements covers the range from 2007 to 2008.

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 Type	Shop
2007-2008	DE3423	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Festoon bulb, 41mm length, end-cap contacts. 12V.	DE3423	Check Price

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Additional Notes

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 or pins.
The DE3423 follows the ANSI standard, which is the specification framework used in the United States and Canada to define bulb dimensions, voltage, and contact type.
The bulb operates at 12 volts, consistent with the standard electrical system voltage found in passenger vehicles.
The 41mm length of the DE3423 refers to the overall span of the bulb from one end cap to the other, which determines physical fitment within the license plate lamp housing.
The Audi RS4 uses the DE3423 for the license plate position across the 2007-2008 model years.
Because festoon bulbs rely on end-cap contact rather than a keyed base, substituting a festoon bulb of a different length risks poor electrical contact or physical incompatibility with the lamp housing, even if the voltage rating matches.