Mercedes-Benz SL500 Map Light Bulb Size

The Mercedes-Benz SL500 map light utilizes bulb size DE3423 or 12961 depending on the specific version required for the interior illumination system. Data for the specified components covers the range from 1999 through 2006.

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
2000-2006	DE3423
1999	12961 (Front and Center)

Bulb Specifications

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

Other Locations

Additional Notes

The Mercedes-Benz SL500 map light uses the DE3423 bulb across the 2000-2006 model years, while the 1999 model year uses the 12961 bulb for both the front and center map light positions.
The DE3423 is an ANSI-standardized festoon bulb, meaning it is defined by a shared North American specification rather than a single manufacturer's part number, which generally allows for substitution between brands that meet the same standard.
Festoon bulbs make electrical contact through metal end caps at both tips of the bulb body rather than through a base socket, and the DE3423 has a body length of 41mm.
The DE3423 operates at 12 volts, consistent with the standard electrical system voltage found in passenger vehicles.
The 12961 is a Philips part number designating a miniature wedge-style bulb of the T10 type, which uses a W2.1x9.5d wedge base and operates at 12 volts with a 5-watt output.
The wedge base of the 12961 relies on wire contacts embedded in the plastic base rather than metal end caps, making it physically incompatible with festoon-style sockets used by the DE3423.
Because the 1999 SL500 uses a wedge-type bulb while the 2000-2006 models use a festoon-type bulb, the two bulb types are not interchangeable despite both operating at 12 volts.