Mercedes-Benz 300D Dome Light Bulb Size

Additional Notes

• The Mercedes-Benz 300D uses the 6411 bulb size for the dome light across all model years listed in the specifications, spanning 1975-1993.
• The 6411 is classified as a festoon bulb, meaning it is cylindrical in shape and mounts by pressing its two end caps into spring-loaded contacts rather than twisting or plugging into a socket.
• The 6411 bulb operates at 12 volts and draws 5 watts, placing it in the low-wattage range typical of interior courtesy lighting.
• The bulb measures 36mm in length and uses an SV8.5 base designation, where SV8.5 refers to the festoon base type with an 8.5mm cap width.
• The 6411 designation follows the ANSI standard, which is the classification system used in the United States and Canada for automotive and specialty bulbs.
• Because the 6411 is an ANSI-standardized part, it is a widely produced bulb size available from multiple manufacturers, and any 6411-rated bulb sharing the same voltage, wattage, length, and base type is considered a direct replacement.
• The SV8.5 base size is a specific festoon subcategory, and festoon bulbs of different base widths or lengths are not interchangeable even if they appear physically similar, as an incorrect length will not seat properly in the spring contacts.