The Chevrolet Colorado side marker utilizes a 12961 bulb size for the lighting components located on the exterior of the vehicle. Data for the specific bulb requirements covers the range from 2017 to 2019.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Chevrolet Colorado uses three distinct bulb types across its front and rear side marker positions: the 12961, 3757NA, and 3057 for earlier model years, and the 7443 for later rear marker applications.
The 12961 is a Philips part number rather than an ANSI industry standard designation. It is a miniature T10 wedge bulb with a W2.1x9.5d base, rated at 12V and 5W, and it serves as the front side marker bulb on the Chevrolet Colorado for model years 2015-2020.
The 3757NA is an ANSI-standard dual-filament T25 wedge bulb with natural amber glass, meaning the amber color is built into the glass envelope itself rather than produced by a colored lens or coating. It is the front side marker bulb for the Colorado across model years 2004-2012.
The front side marker position shifted from the 3757NA to the 12961 between the 2012 and 2015 model years, reflecting a change in bulb type, filament count, and wattage between the two generations of the Colorado.
The 7443 is an ANSI-standard dual-filament T20 wedge bulb rated at 12V with a high filament of 21W and a low filament of 5W. It serves as the rear side marker bulb on the Colorado for model years 2015-2020.
The 3057 is an ANSI-standard dual-filament T25 wedge bulb rated at 12V with a high filament of 27W and a low filament of 7W. It is the rear side marker bulb for the Colorado for model years 2009-2012.
The 3057 and 7443 are both dual-filament wedge bulbs operating at 12V, but they differ in physical size and wattage ratings, making them non-interchangeable despite serving the same rear side marker function across different Colorado generations.
The 3757NA and 12961 are also non-interchangeable in the front side marker position. The 3757NA is a dual-filament T25 bulb with natural amber glass, while the 12961 is a single-filament T10 bulb with a W2.1x9.5d base, representing a fundamentally different bulb format.