Mercedes-Benz 300SD Map Light Bulb Size

The Mercedes-Benz 300SD map light requires a bulb size of 3893 for the interior lighting system. Data for the specified component covers the range from 1978 to 1980.

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
1978-1980	3893

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base, specialty application. 12V.	3893

Other Locations

Additional Notes

The Mercedes-Benz 300SD uses the 3893 bulb for the map light across the 1978-1980 model years.
The 3893 is an ANSI-standardized bulb, meaning its physical and electrical specifications conform to a defined industry standard recognized in the United States and Canada.
This bulb operates on a 12-volt electrical system, consistent with standard automotive DC voltage.
The 3893 carries a BAY15d bayonet base, which is a dual-contact offset-pin fitting. The two pins are positioned at different heights to ensure the bulb can only be inserted in one orientation, preventing incorrect installation.
As a dual-filament bulb, the 3893 contains two separate filaments within a single envelope, allowing it to serve more than one lighting function through independent circuits.
The BAY15d base type is a specialty fitment, meaning direct substitution with bulbs carrying different base configurations, such as the single-contact BA15s, would result in an incompatible fit for the 300SD map light socket.