The INFINITI G25 front turn signal requires a 7443NA bulb size while the rear turn signal uses a 7440 bulb size. The replacement chart covers 2011 to 2012 model years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The INFINITI G25 uses two distinct T20 wedge bulb types across its front and rear turn signal positions for the 2011-2012 model years.
The T20 wedge base is a standardized form factor, meaning both the 7443NA and 7440 share the same physical socket style despite differing in filament count.
The front turn signal on the G25 (2011-2012) takes the 7443NA, a dual-filament bulb rated at 12V with a 21W main filament and a 5W secondary filament, indicating the position serves more than one lighting function.
The natural amber glass of the 7443NA produces its amber turn signal color directly from the bulb itself, rather than relying on a colored lens housing to filter a clear light source.
The rear turn signal for the 2011-2012 G25 uses the 7440, a single-filament bulb rated at 12V and 21W, dedicated solely to one lighting function at that position.
Although the 7443NA and 7440 share the T20 wedge form factor, the 7443NA carries a second filament and an amber coating that the 7440 does not, making the two bulbs non-interchangeable despite their physical similarity.
Both the 7443NA and 7440 conform to ANSI standards applicable in the United States and Canada, reflecting a North American market specification for the G25.
Installing a 7440 in place of a 7443NA would eliminate the secondary 5W filament function at the front turn signal position, as the 7440 lacks that circuit entirely.