The INFINITI M45 front turn signal bulb size measures 7440NA or 1157NA, while the rear turn signal bulb size measures 7440NA. The replacement chart covers vehicle production years spanning 2003 to 2010 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 7440NA is the most widely used bulb across the Infiniti M45 turn signal specifications, appearing in both front and rear positions for the 2006-2010 model years, as well as the rear position for 2003-2004.
The 7440NA is a single-filament wedge bulb using the T20 base type, rated at 12V and 21W, and meets ANSI standards for the US and Canadian markets.
The natural amber glass of the 7440NA produces its amber turn signal color directly through the glass envelope rather than through a colored lens or housing.
The 1157NA differs from the 7440NA in both base type and filament count. It uses a BAY15d bayonet base with dual filaments rated at 21W and 5W, making it capable of serving two lighting functions within a single bulb.
The Infiniti M45 (2003-2004) front turn signal uses the 1157NA, while the rear turn signal for those same years uses the 7440NA, meaning the front and rear positions are not interchangeable for those model years.
For 2006-2010, the front and rear turn signals share the same 7440NA bulb, which means a single bulb type covers both positions across those years.
The 7440NA and 1157NA are not interchangeable. The T20 wedge base of the 7440NA and the BAY15d bayonet base of the 1157NA are physically incompatible socket types.
Both the 7440NA and 1157NA share the same 12V operating voltage and the same natural amber glass construction, though their filament configurations and base types differ.