Subaru Ascent Tail Light Bulb Size

The Subaru Ascent tail light requires a unique bulb size of 12961 for the rear lighting assembly. Data for the specified component covers the range from 2023 to 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 Type	Shop
2023-2024	12961	Check Price

Bulb Specifications

Description	Type	Shop
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12961	Check Price

Other Locations

Additional Notes

The 12961 is a Philips part number designating a miniature wedge bulb in the T10 form factor. It uses a W2.1x9.5d base, which is a wedge-style base that requires no locking tabs or rotation to seat, relying instead on tension from the socket walls to hold the bulb in place.
The 12961 operates at 12 volts and 5 watts, placing it in the low-wattage range typical of auxiliary lighting functions such as tail, parking, and side marker positions rather than primary illumination.
The Subaru Ascent uses the 12961 bulb for the tail light position across the 2023-2024 model years.
The T10 form factor and W2.1x9.5d base are widely shared across many vehicle makes and positions, meaning physically similar bulbs from other part numbers may fit the socket but not necessarily meet the same voltage or wattage rating as the 12961.