Chevrolet Equinox Dome Light Bulb Size

Additional Notes

• The Chevrolet Equinox dome light uses two distinct bulb types across its model years: the 12961 for 2010-2020 and the 561 for 2005-2009.
• The 12961 is a Philips part number designating a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12V and 5W.
• The 561 is an ANSI-standardized festoon bulb recognized across the US and Canadian markets, rated at 12V and 12W, with a 44mm length and end-cap contacts.
• The wedge base of the 12961 locks into its socket by friction through the base pins, while the 561 festoon bulb makes contact through metal caps at each end of the bulb body.
• The 561 draws 12W compared to the 12961's 5W, meaning the two bulb types are not electrically interchangeable despite both operating at 12V.
• The T10 wedge form factor of the 12961 and the festoon form factor of the 561 are physically incompatible with each other's sockets, making cross-substitution between the two generations impossible without socket modification.
• The 12961 designation is a manufacturer-specific Philips number rather than a universal ANSI code, so equivalent bulbs from other manufacturers are identified by their T10 wedge form and W2.1x9.5d base specification rather than by that number alone.
• The 44mm length of the 561 festoon bulb is a critical fitment factor, as festoon bulbs are produced in multiple lengths and only the 44mm variant is specified for the applicable Equinox model years.