Chevrolet Colorado Dome Light Bulb Size

Additional Notes

• The 12961 is a miniature wedge bulb in the T10 form factor, using a W2.1x9.5d base. It operates at 12V and draws 5W, making it a low-wattage lamp relative to the 561 it replaced in later Colorado applications.
• The 561 is an ANSI-standardized festoon bulb with a 44mm length and end-cap contacts. It operates at 12V and draws 12W, more than double the wattage of the 12961 used in later model years.
• The Chevrolet Colorado (2015-2016, 2019-2020, 2023-2024) uses a single dome light bulb size of 12961 with no positional distinction noted in the specifications.
• The 2017-2018 Colorado specifies the 12961 bulb for two distinct positions: Front Center and Rear Center, indicating a two-dome interior lighting arrangement for those model years.
• The 2004-2008 Colorado uses the 561 festoon bulb for dome lighting. The festoon format is held in place by spring-loaded end caps rather than a wedge socket, making it physically incompatible with the W2.1x9.5d wedge socket used in later model years.
• The T10 wedge base of the 12961 and the end-cap festoon format of the 561 are mechanically distinct socket types. A 561 cannot be installed in a T10 wedge socket, and vice versa, regardless of voltage compatibility.
• The 12961 is a Philips-assigned part number rather than an ANSI industry standard designation, whereas the 561 carries an ANSI standard classification recognized across the US and Canada.
• The wattage difference between the two bulb types (5W for the 12961 versus 12W for the 561) reflects a reduction in power consumption in the dome lighting circuit across the two generations of Colorado covered by these specifications.