Saturn Relay front turn signal bulbs use 3157NA size while rear turn signal bulbs use 3157 size. The replacement chart covers 2005 to 2007 production 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 Saturn Relay uses the 3157NA bulb for the front turn signal across the 2005-2007 model years, while the rear turn signal uses the 3157 across the same span.
Both the 3157NA and 3157 are dual-filament T25 wedge bulbs rated at 12V with a 27W/7W power draw, meaning the higher wattage filament handles the turn signal function and the lower wattage filament serves a secondary role such as running or parking light duty.
The key distinction between the two bulbs is the glass envelope. The 3157NA features natural amber-tinted glass, while the 3157 uses clear glass.
Because the front position on the Saturn Relay specifies the 3157NA, the amber coloring is built into the bulb itself rather than relying solely on a colored lens to produce the required amber turn signal output.
Both bulbs conform to ANSI standards recognized in the United States and Canada, placing them within a standardized performance and dimensional classification system.
The 3157 and 3157NA share the same T25 wedge base and identical electrical ratings, which means they are physically interchangeable, though substituting a clear 3157 in a front socket designed for the 3157NA may affect the amber color output if the housing lens is also clear.