INFINITI FX35 Back Up Light Bulb Size

The INFINITI FX35 back up light utilizes 7440 and 921 bulb sizes for the rear illumination components. Data for the specified vehicle covers the period from 2003 through 2012.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
2009-2012	7440
2003-2008	921

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament wedge bulb (T20). 12V, 21W.	7440
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921

Other Locations

Additional Notes

The INFINITI FX35 back up light specifications cover the 2003-2012 model years, with two distinct bulb sizes used across that span.
The 7440 is a single-filament wedge bulb following the T20 form factor, rated at 12V and 21W, and conforming to the ANSI standard for the US and Canada markets.
The 921 is a wedge bulb following the T15 form factor, rated at 12V and 16W, and also conforming to the ANSI standard for the US and Canada markets.
The 2009-2012 FX35 model years use the 7440 bulb for the back up light position.
The 2003-2008 FX35 model years use the 921 bulb for the back up light position.
The T20 and T15 designations refer to the outer width of the wedge base, with T20 being physically larger than T15, making the two bulb types non-interchangeable despite sharing the same 12V operating voltage.
The wattage difference between the two bulbs is notable: the 7440 draws 21W while the 921 draws 16W, meaning the 7440 produces a higher light output at the back up light position.
The fitment change between the 2008 and 2009 model years reflects a shift from the 921 to the 7440, and substituting one for the other across that boundary would result in an incorrect fit.