Mercedes-Benz S600 License Plate Bulb Size

Additional Notes

• The Mercedes-Benz S600 license plate position uses two distinct bulb types across its model years: the 12961 (a T10 wedge type) for 2007-2013 and the DE3423 (a festoon type) for 1994-2006, with the exception of 2000, which is not present in the specifications.
• The 12961 is a Philips part number designating a miniature wedge bulb in the T10 form factor, operating at 12 volts and rated at 5 watts, with a W2.1x9.5d base.
• The W2.1x9.5d base on the 12961 bulb refers to a wedge-style base where the glass envelope itself acts as the retention mechanism, with no separate metal base pins.
• The DE3423 is an ANSI-standardized designation recognized across the United States and Canada, identifying a festoon-style bulb with a 41mm length and end-cap contacts at both terminals.
• Festoon bulbs such as the DE3423 make electrical contact through metal caps at each end of the cylindrical glass tube, which is a fundamentally different contact geometry than the wedge base used by the 12961.
• Because the T10 wedge and the 41mm festoon use incompatible socket types, the 12961 and DE3423 are not interchangeable, and substituting one for the other in the S600 requires a socket that matches the specific model year.
• The DE3423's 41mm length is a standardized festoon size, meaning bulbs from multiple manufacturers conforming to that length and end-cap contact style are generally cross-compatible with one another within that designation.
• Both bulb types operate on a 12-volt circuit, which is consistent with standard automotive electrical systems.