Nissan Altima Dome Light Bulb Size

Additional Notes

• The Nissan Altima dome light uses two distinct bulb types across its model years: the DE3175 festoon bulb and the 12961 miniature wedge bulb, with the DE3175 appearing across the greater portion of the listed model years.
• The DE3175 is an ANSI-standardized festoon bulb rated at 12 volts. It measures 31mm in length and makes electrical contact through end-cap terminals at each end of the bulb body. This standard is recognized across the United States and Canada.
• The 12961 is a Philips part number designating a T10 miniature wedge bulb. It uses a W2.1x9.5d wedge base, operates at 12 volts, and draws 5 watts. The wedge base design relies on wire contacts that grip the base rather than a separate socket pin.
• The Nissan Altima (2023-2024) uses the 12961 bulb for the dome light, while model years 1993-2006 and 2016-2020 use the DE3175.
• The DE3175 and 12961 use fundamentally different base types, a festoon end-cap versus a wedge base, making them physically incompatible with each other's sockets. These two bulb types are not interchangeable.
• The T10 wedge designation on the 12961 refers to the bulb's tubular form factor, a classification used to group miniature bulbs by shape within the automotive and lighting industries.
• The W2.1x9.5d base code on the 12961 follows IEC naming conventions, where 2.1 refers to the base width in millimeters and 9.5 refers to the pin spacing, providing a precise reference for socket compatibility.
• The DE3175 designation combines a festoon-style form factor indicator with a 31mm length specification, which is the critical fitment factor for festoon bulbs, as incorrect lengths will prevent proper contact with the socket terminals.