The INFINITI I35 front turn signal uses a 7440 bulb size while the rear turn signal requires a PY21W bulb size. The replacement chart covers 2002 to 2004 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 I35 uses the 7440 bulb for the front turn signal across the 2002-2004 model years.
The 7440 is a single-filament wedge bulb in the T20 form factor, rated at 12V and 21W, and follows the ANSI standard used in the United States and Canada.
The rear turn signal on the I35 uses the PY21W bulb across the same 2002-2004 model years.
The PY21W is a single-filament amber bulb rated at 12V and 21W, built to the ECE standard used in Europe and other worldwide markets.
While both the 7440 and PY21W share the same voltage and wattage ratings, they are not interchangeable due to their different base types. The 7440 uses a wedge base, while the PY21W uses a BAU15s bayonet base.
The amber coloring of the PY21W is built into the bulb itself, whereas the 7440 relies on the lens housing to produce an amber signal output.
The BAU15s bayonet base of the PY21W has offset pins, which prevents it from being substituted with standard BA15s base bulbs that share a similar physical profile.