Mercedes-Benz C320 Map Light Bulb Size

Additional Notes

• The Mercedes-Benz C320 map light uses two distinct bulb types across its production run, with the 6411 fitted to 2003-2005 models and the 12961 fitted to 2001-2002 models.
• The 6411 is an ANSI-standardized bulb, meaning its specifications are governed by a recognized industry body and the designation is consistent across manufacturers in the United States and Canada.
• The 6411 is a festoon-type bulb, a cylindrical form factor that seats at both ends rather than using a single base socket, with a length of 36mm and an SV8.5 base.
• The 12961 is a Philips part number designation rather than an ANSI standard, meaning it originates from a manufacturer's own catalog and may correspond to equivalent bulbs under different part numbers from other brands.
• The 12961 is a T10 miniature wedge bulb, a form factor that uses a wedge-shaped plastic base to friction-fit into its socket, with a W2.1x9.5d base specification.
• Both the 6411 and 12961 operate at 12 volts and 5 watts, making their electrical demands identical despite their physically incompatible form factors.
• The SV8.5 base of the 6411 and the W2.1x9.5d wedge base of the 12961 are not interchangeable, as each requires a differently shaped socket in the vehicle's map light housing.
• The physical incompatibility between the festoon and wedge base types means a bulb specified for 2003-2005 models cannot be fitted to a 2001-2002 C320 map light socket, and vice versa.