Mercedes-Benz ML320 Dome Light Bulb Size

Additional Notes

• The Mercedes-Benz ML320 dome light specifications reference two distinct bulb types across its model years: the 6411 festoon bulb and the 12961 miniature wedge bulb.
• The 6411 is an ANSI-standardized bulb recognized across the US and Canadian markets, operating at 12V and 5W with an SV8.5 base and a 36mm festoon form factor.
• A festoon bulb is a cylindrical lamp that mounts by pressing its end caps into spring clips, which is a common interior lighting configuration in passenger vehicles.
• The 12961 is a Philips part number designating a T10 miniature wedge bulb with a W2.1x9.5d base, also rated at 12V and 5W.
• A wedge base bulb relies on its glass envelope and wire leads to friction-fit into a socket, rather than using a separate metal base with pins or caps.
• The ML320 from 1998-2007 uses the 6411 festoon bulb for its dome light, while the 2008-2009 model years specify the 12961 wedge bulb, but only for the rear position.
• The 6411 and 12961 share identical voltage and wattage ratings, but their base types are physically incompatible, meaning one cannot substitute for the other without a socket adapter or modification.
• The rear-position designation on the 2008-2009 12961 fitment indicates that the dome light system in those years involves more than one bulb position, with the 12961 assigned specifically to the rear.