Mercedes-Benz 230 Map Light Bulb Size

The Mercedes-Benz 230 map light requires a bulb size of 12821 for the interior lighting system. Data for the specific bulb requirements covers the range of 1966 to 1967.

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
1966-1967	12821

Bulb Specifications

Description	Bulb Size
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12821

Other Locations

Additional Notes

The 12821 is a Philips part number designating a miniature wedge bulb in the T10 form factor, fitted with a W2.1x9.5d base. It operates at 12 volts and draws 5 watts.
The W2.1x9.5d base is a wedge-type connection, meaning the bulb is held in place by tension from the socket rather than by a separate locking mechanism or bayonet pins.
The Mercedes-Benz 230 uses the 12821 bulb for the map light across the 1966-1967 model years.
The T10 designation refers to the bulb's tubular envelope, with a width of 10 thirty-seconds of an inch. This is one of the most widely used miniature bulb formats in automotive interior lighting applications.
At 5 watts and 12 volts, the 12821 produces a modest light output consistent with close-range interior tasks such as map reading, where broad illumination is not required.