Subaru Outback Dome Light Bulb Size

The Subaru Outback dome light utilizes a DE3175 bulb size for interior illumination within the cabin area. Provided data covers a specific range of production from 2008 through 2021.

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
2008-2021	DE3175

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 31mm length, end-cap contacts. 12V.	DE3175

Other Locations

Additional Notes

The Subaru Outback dome light takes a DE3175 bulb across all listed model years from 2008 to 2021.
The DE3175 is a festoon-type bulb, meaning it is cylindrical in shape and makes electrical contact through metal caps at each end rather than through a base socket.
Festoon bulbs are held in place by spring-loaded clips within the fixture, with the end caps pressing against the contacts to complete the circuit.
The DE3175 has a nominal length of 31mm, which is the critical fitment factor for festoon bulbs, as a longer or shorter bulb will not seat correctly in the spring clips.
The bulb operates on a 12-volt system, consistent with standard automotive electrical architecture.
The DE3175 designation follows ANSI standards recognized in both the United States and Canada, meaning the specification applies uniformly across North American market vehicles.
Because the DE3175 is an ANSI-standardized type, it is interchangeable with any other bulb carrying the same designation regardless of manufacturer, provided the 31mm length and end-cap contact design are maintained.
Festoon bulbs of different length designations, such as the 28mm DE3021 or the 36mm DE3423, are not interchangeable with the DE3175 even though they share the same festoon form factor.