Audi A4 Map Light Bulb Size

The Audi A4 map light utilizes bulb size 12961 or DE3423 depending on the specific version of the vehicle. Available data covers the span from 1996 through 2016.

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
2007-2016	12961
1999	12961
1996-1997	DE3423

Bulb Specifications

Description	Bulb Size
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12961
ANSI standard (US & Canada). Festoon bulb, 41mm length, end-cap contacts. 12V.	DE3423

Other Locations

Additional Notes

The Audi A4 map light uses the 12961 bulb across the 2007-2016 model years, as well as the 1999 model year.
The 12961 is a Philips part number designating a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12V and 5W.
The T10 designation refers to the bulb's tubular shape, with the wedge base designed to friction-fit directly into a socket without a separate locking mechanism.
The 1996-1997 Audi A4 map light uses the DE3423 bulb instead, which is an ANSI-standard festoon type rated at 12V.
The DE3423 is a 41mm festoon bulb that makes contact through metal end caps at each tip, a fitment style physically incompatible with the wedge socket used by the 12961.
Because the 12961 and DE3423 use different base types, a wedge-socket housing and a festoon-socket housing are not interchangeable, and substituting one bulb for the other in the wrong socket is not possible without modification.
The W2.1x9.5d base designation on the 12961 is an IEC standard code specifying the contact width and pin spacing, which determines socket compatibility across different manufacturers' products sharing that base type.