Toyota 4Runner Dome Light Bulb Size

Additional Notes

• The DE3175 is the dominant dome light bulb across the Toyota 4Runner specifications, appearing in the vast majority of model years from 1990 through 2024 across the general dome, front dome, and rear dome light positions.
• The DE3175 is an ANSI-standard festoon bulb rated at 12V, measuring 31mm in length with end-cap contacts at each end. This contact style distinguishes festoon bulbs from wedge-base types, as the bulb seats by pressing its metal caps into spring-loaded holders rather than inserting a tapered base.
• The DE3425 is also a festoon bulb with end-cap contacts and a 12V rating, but its length is 41mm rather than 31mm. The 1995 Toyota 4Runner dome light calls for this longer DE3425, making it physically incompatible with the DE3175 sockets used in other model years.
• The 2021 Toyota 4Runner dome light specification lists the 168 bulb rather than the DE3175. The 168 is a T10 miniature wedge bulb rated at 12V and 4.9W, which uses an entirely different base style and is not interchangeable with festoon-type bulbs.
• Because the 2021 model year uses a wedge-base T10 socket and surrounding years use festoon sockets, the 2021 bulb is not a drop-in substitute for any adjacent model year, and vice versa.
• All three bulb types listed in the specifications, the DE3175, DE3425, and 168, conform to ANSI standards applicable in the United States and Canada.
• For the front dome light position, the DE3175 is specified for the 1996 and 2005-2009 model years. This sub-position data covers a narrower range of years than the general dome light data.
• The rear dome light position for the 2017-2019 Toyota 4Runner specifies the DE3175 with a center designation, indicating placement at the center of the rear cabin area. The same DE3175 bulb is also listed for the rear dome light in the 1996 and 2005-2009 model years without a positional qualifier.
• Although the DE3175 and DE3425 share the same festoon form factor and end-cap contact style, their differing lengths mean a DE3425 will not seat correctly in a 31mm festoon holder, and a DE3175 will fit loosely or fail to make contact in a 41mm festoon holder.
• The 1995 model year stands as the only entry across all listed positions and sub-positions to require the DE3425, making it a notable exception in an otherwise DE3175-dominated fitment record for the 4Runner.