The GMC Acadia tail light requires a 7440 bulb size for the specific lighting component located at the rear of the vehicle. Data for the bulb covers the range from 2013 to 2016.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 7440 bulb is the sole bulb type listed across all tail light positions in the GMC Acadia specifications provided.
The 7440 is a single-filament wedge bulb built to the T20 form factor, rated at 12 volts and 21 watts.
As a single-filament design, the 7440 serves one lighting function per socket, distinguishing it from dual-filament variants such as the 7443, which shares the same T20 wedge base but carries two filaments.
The T20 wedge base is a push-in connector type, meaning the bulb is retained by the socket walls rather than by a bayonet or screw mechanism.
The 7440 conforms to ANSI standards applicable in both the United States and Canada, indicating a standardized specification recognized across North American markets.
The GMC Acadia (2013-2016) uses the 7440 in the outer tail light position.
For the 2017-2018 model years, the 7440 is specified for both the inner and outer tail light positions.
Because the 7443 shares the same T20 wedge base as the 7440, it is physically capable of fitting a 7440 socket, though the two bulbs are not functionally interchangeable due to the difference in filament count.