The GMC Terrain brake light utilizes 7444NA, 7440, and 3057 bulb sizes depending on the specific version of the vehicle. Data provided covers a range from 2010 through 2024.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The GMC Terrain uses three distinct brake bulb types across its model years: the 7444NA, 7440, and 3057, all of which conform to ANSI standards recognized in both the United States and Canada.
The 3057 is a dual-filament wedge bulb in the T25 form factor, rated at 12V with a 27W high filament and a 7W low filament. It serves as the brake bulb for the GMC Terrain across the 2010-2017 model years.
The 7440 is a single-filament wedge bulb in the T20 form factor, rated at 12V and 21W. Unlike the 3057, it carries only one filament, which means the two types are not interchangeable despite both being wedge-base designs.
The 7444NA shares the T20 form factor and 12V, 21W/5W dual-filament configuration with other T20 variants, but its natural amber glass distinguishes it physically and functionally from clear-lens equivalents.
For the 2023-2024 model years, the GMC Terrain specifies the 7444NA for the brake bulb position, making it the most recent bulb type used in this application.
The T20 and T25 designations refer to the outer width of the wedge base, with T25 being wider than T20. Because the socket sizes differ, 3057 bulbs and 7440-series bulbs are not physically interchangeable.
For the 2018-2020 model years, the 7440 brake bulb fitment on the GMC Terrain is conditional, applying specifically to vehicles equipped with HID headlamps.
A separate Outer Brake sub-position is specified for the 2017-2019 model years. The 2017 Outer Brake position uses the 3057, while the 2018-2019 positions use the 7440, without the HID headlamp condition noted for the standard brake position in those same years.
The 7444NA and 7440 both occupy the T20 form factor, but the 7444NA is dual-filament while the 7440 is single-filament. This difference in filament count makes them functionally distinct despite sharing the same base type.
The 3057 operates at a higher wattage on its primary filament (27W) compared to the 7444NA (21W) and the 7440 (21W), reflecting the different output levels associated with the T25 versus T20 bulb families.