Mercedes-Benz CLA45 AMG Dome Light Bulb Size

The Mercedes-Benz CLA45 AMG dome light uses bulb size 12961 and bulb size 6411 for the interior lighting system. Available data for the specified components covers the range from 2014 to 2020.

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
2020	12961
2014-2019	6411

Bulb Specifications

Description	Bulb Size
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12961
ANSI standard (US & Canada). Festoon bulb, 36mm length, SV8.5 base. 12V, 5W.	6411

Other Locations

Additional Notes

The Mercedes-Benz CLA45 AMG uses two distinct dome light bulb types across its 2014-2020 model years: the 6411 festoon bulb and the 12961 miniature wedge bulb.
The 6411 is an ANSI-standardized bulb recognized across the US and Canadian markets, operating at 12V and 5W with an SV8.5 base and a 36mm festoon length.
The SV8.5 base designation on the 6411 refers to a festoon-style contact base where the bulb is held in place by spring clips at each end rather than a socket.
The 12961 is a Philips part number designating a T10 miniature wedge bulb with a W2.1x9.5d base, also rated at 12V and 5W.
The W2.1x9.5d base on the 12961 is a wedge-type fitting where the glass envelope itself acts as the retention mechanism, with no separate socket pins.
The CLA45 AMG (2014-2019) uses the 6411 festoon bulb for the dome light, while the 2020 model year uses the 12961 wedge bulb instead.
Although both bulb types share the same 12V, 5W electrical rating, their base types are physically incompatible, meaning the 6411 and 12961 are not interchangeable despite identical power specifications.