Cadillac XT5 Trunk Bulb Size

The Cadillac XT5 trunk light requires a 12961 bulb size for proper installation and function within the rear cargo area. Data for the specific component covers the range from 2017 to 2019.

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
2017-2019	12961

Bulb Specifications

Description	Bulb Size
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12961

Other Locations

Additional Notes

The 12961 is the trunk bulb size for the Cadillac XT5 across the 2017-2019 model years.
The 12961 is a Philips part number designating a miniature wedge bulb in the T10 form factor.
T10 refers to the bulb's tubular shape, with the number indicating its width in tenths of an inch, making it one of the most widely used miniature bulb formats in automotive interior and cargo lighting.
The 12961 uses a W2.1x9.5d base, which is the standard wedge-type base for T10 bulbs, relying on spring tension from the socket rather than a locking mechanism to maintain contact.
The bulb operates at 12 volts and 5 watts, consistent with low-power interior lighting applications such as trunk illumination.
The W2.1x9.5d base designation is shared across many T10 miniature wedge bulbs from various manufacturers, meaning the 12961 belongs to a broadly interchangeable bulb family within that base type.