Mercedes-Benz 300TD Dome Light Bulb Size

The Mercedes-Benz 300TD dome light requires a 6411 bulb size for proper illumination within the interior cabin area. Available data for the specified lighting component covers the period from 1979 to 1987.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1987	6411
1979-1985	6411

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 36mm length, SV8.5 base. 12V, 5W.	6411

Other Locations

Additional Notes

The Mercedes-Benz 300TD uses the 6411 bulb for the dome light across all listed model years from 1979-1987.
The 6411 is a festoon-type bulb, meaning it is cylindrical in shape and mounts by pressing between two spring clips at each end rather than inserting into a socket.
The 6411 bulb has a length of 36mm, which is a critical fitment factor, as festoon bulbs must match the span between the fixture's contact clips to seat and make electrical contact properly.
The base designation for the 6411 is SV8.5, referring to a festoon base with an 8.5mm cap width at each end.
The 6411 operates at 12 volts and 5 watts, consistent with standard low-draw interior lighting in 12-volt automotive electrical systems.
The 6411 designation follows the ANSI standard, which applies to the United States and Canada, meaning this bulb coding system is specific to those markets.
Because festoon bulbs are sized by physical length, substituting a festoon bulb of a different length, such as a 31mm or 41mm unit, would result in an improper fit in the 300TD dome light fixture.