The Isuzu Axiom front turn signal requires either 1157NA or 1034NA bulb size, while the rear turn signal uses 7440 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 Isuzu Axiom uses three distinct bulb types across its turn signal positions: the 1157NA and 1034NA for the front, and the 7440 for the rear.
The 1157NA is a dual-filament bulb with a BAY15d bayonet base, natural amber glass, rated at 12V with a 21W main filament and a 5W secondary filament. It fits the front turn signal on the 2003-2004 Axiom.
The 1034NA shares the same BAY15d bayonet base and natural amber glass construction as the 1157NA and carries the same 12V, 21W/5W rating, but it is a distinct variant of the 1157 series. It fits the front turn signal on the 2002 Axiom only.
Although the 1157NA and 1034NA share the same base type and voltage-wattage ratings, they are separate part numbers and are not confirmed as interchangeable within these specifications.
The BAY15d bayonet base found on both the 1157NA and 1034NA is a dual-contact base, which is what allows the bulb to operate two filaments independently within a single housing.
The 7440 is a single-filament wedge bulb in the T20 form factor, rated at 12V and 21W. It serves as the rear turn signal bulb across all three model years of the Axiom, covering 2002-2004.
Because the 7440 is a single-filament bulb, it is not suited for applications requiring a secondary low-wattage filament, such as combined turn and parking light functions.
All three bulb types listed carry ANSI standard designations valid for the US and Canadian markets.