Buick Encore GX Dome Light Bulb Size

The Buick Encore GX dome light utilizes 12961 and 6411 bulb sizes for interior illumination. Data for the specified components covers the period from 2020 through 2024.

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
2023-2024	12961
2021	12961
2020	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 12961 is a miniature wedge bulb using the T10 form factor with a W2.1x9.5d base, rated at 12V and 5W. The T10 designation refers to a tubular bulb roughly 10/8 of an inch wide, and the W2.1x9.5d base describes a wedge-type connection where the glass envelope itself acts as the retaining mechanism rather than a metal cap.
The 6411 is a festoon bulb with an SV8.5 base and a 36mm length, also rated at 12V and 5W. Festoon bulbs are cylindrical in shape and mount by pressing between two spring contacts at each end, making the length a critical fitment factor.
Although both the 12961 and 6411 share the same 12V, 5W electrical rating, they are physically incompatible with each other. The wedge base of the 12961 and the festoon contact design of the 6411 require entirely different socket types.
The Buick Encore GX uses the 12961 bulb for the dome light across the 2021 and 2023-2024 model years, making it the more widely applicable of the two bulb types represented in these specifications.
The 2020 Buick Encore GX uses the 6411 festoon bulb, which follows the ANSI standard recognized in both the United States and Canada. The 12961 is a Philips part number designation rather than an ANSI standard reference.