Mercedes-Benz G550 Dome Light Bulb Size

Additional Notes

• The Mercedes-Benz G550 uses the 6411 bulb size for the dome light across the 2009-2018 model years.
• The 6411 is an ANSI-standardized bulb designation recognized in both the United States and Canada, meaning it conforms to a defined set of electrical and physical characteristics shared across manufacturers.
• The 6411 is a festoon-style bulb, which means it is cylindrical in shape and mounts by pressing its two end caps into spring-loaded clips rather than inserting into a socket with a traditional base pin.
• The 6411 bulb has a length of 36mm, which is a critical fitment factor, as festoon bulbs must match the spacing of the fixture's retaining clips to seat correctly.
• The 6411 uses an SV8.5 base, a designation that refers to the 8.5mm cap width at each end of the festoon body, which must correspond to the clip width in the dome light housing.
• The 6411 operates at 12 volts, consistent with the standard electrical system voltage found in passenger vehicles.
• The 6411 is rated at 5 watts, placing it in the low-wattage category typical of interior courtesy lighting applications.
• Because festoon bulbs are defined by both length and base width, substituting a festoon bulb of a different length or cap size, even at the same voltage and wattage, would result in an improper fit in the G550 dome light housing.