Honda Ridgeline Map Light Bulb Size

Additional Notes

• The Honda Ridgeline map light uses two distinct bulb types across its production span: the 12961 (T10 wedge) for 2017-2024 models and the DE3175 (31mm festoon) for 2006-2014 models.
• The 12961 is a Philips part number designating a miniature T10 wedge bulb with a W2.1x9.5d base, rated at 12V and 5W.
• The W2.1x9.5d base is a wedge-type fitting where the bulb's glass envelope itself forms the base, with no separate metal shell, and the electrical contacts are embedded in the glass pinch at the bottom.
• The DE3175 is an ANSI-standardized festoon bulb recognized across the US and Canadian markets, measuring 31mm in length with end-cap contacts at both terminals.
• Festoon bulbs make contact at each end of the cylindrical body rather than at a base, which means they are not interchangeable with wedge-base sockets regardless of voltage or wattage compatibility.
• The Honda Ridgeline (2017) marks the transition point between the two bulb types, with the DE3175 festoon used through 2014 and the 12961 wedge adopted from 2017 onward.
• Both bulb types operate on a 12V circuit, which is standard for automotive interior lighting, though the DE3175 specification does not carry a listed wattage rating in these specifications.
• The T10 wedge format of the 12961 is a widely used automotive interior bulb size, which means aftermarket LED replacements in the T10/W5W category are generally produced to fit the same W2.1x9.5d socket used in 2017-2024 Ridgeline map lights.