The INFINITI FX50 front turn signal requires a 7440NA bulb size while the rear turn signal uses a 7440 bulb size. The replacement chart covers 2009 to 2013 model years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 7440NA and 7440 are the two bulb types specified for the Infiniti FX50 across all listed model years (2009-2013), covering the front and rear turn signals respectively.
Both the 7440NA and 7440 are single-filament wedge bulbs classified under the T20 form factor, operating at 12 volts and rated at 21 watts.
The single-filament design means each bulb serves one dedicated function, as opposed to dual-filament bulbs that handle two functions such as turn signaling and braking simultaneously.
The 7440NA is specified for the front turn signal position on the FX50 across all listed model years. The "NA" suffix denotes natural amber glass, which filters the light output to produce an amber color without relying on an amber-tinted lens or housing.
The 7440 is specified for the rear turn signal position. It shares the same T20 wedge base, voltage, and wattage as the 7440NA but lacks the natural amber glass coating.
Because the 7440NA and 7440 share the same T20 wedge base and electrical ratings, they are physically interchangeable in terms of socket fitment. However, substituting a 7440 for a 7440NA in the front position would alter the color output if the housing relies on the bulb's amber glass for the required amber signal color.
Both bulb types conform to ANSI standards applicable in the United States and Canada, indicating compliance with standardized dimensional and performance specifications for those markets.