The Saab 9-7x uses 4157NA and 5702AK bulbs for front turn signals and 3157NA bulbs for rear turn signals, with each size corresponding to specific vehicle applications. The replacement chart covers 2005 through 2009 model years with bulb specifications for each production period.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Saab 9-7x rear turn signal position uses the 3157NA bulb across all model years covered in the specifications, from 2005-2009.
The 3157NA is an ANSI-standardized dual-filament wedge bulb in the T25 form factor, rated at 12V with a 27W high filament and 7W low filament, and features natural amber glass rather than a coating.
The 4157NA shares the same T25 form factor, voltage, and wattage ratings as the 3157NA, and is also an ANSI-standardized type with natural amber glass.
Despite their near-identical electrical and physical specifications, the 4157NA and 3157NA carry distinct ANSI designations, which indicates they are not confirmed as interchangeable by the specifications.
The front turn signal position on the Saab 9-7x does not use a single bulb type across all years. The 2006, 2007, and 2009 model years call for the 4157NA, while the 2005 and 2008 model years call for the 5702AK.
The 5702AK is a Sylvania-specific part number rather than an ANSI standard designation, and it represents an amber-coated variant of the 3157 bulb rather than one made with natural amber glass.
Because the 5702AK is a manufacturer-specific designation, its interchangeability with ANSI-numbered bulbs such as the 3157NA or 4157NA is not established within the provided specifications.
All three bulb types referenced in the specifications share the T25 wedge form factor and a 12V, 27W/7W dual-filament configuration, meaning the primary differences between them are in glass treatment and standardization origin rather than electrical output.
The natural amber glass construction of the 4157NA and 3157NA produces amber-colored light through the glass itself, whereas the 5702AK achieves its amber output through a surface coating applied over clear glass.