Saab 9-3 Daytime Running Light Bulb Size

The Saab 9-3 daytime running light requires a 4157 bulb size for the specific lighting component located at the front of the vehicle. Data for the required bulb covers the range from 2008 through 2011.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
2010-2011	4157
2008-2009	4157 (With HID Headlamps)

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	4157

Other Locations

Additional Notes

The 4157 is an ANSI-standardized bulb type recognized across the United States and Canada, making it a widely available replacement in North American markets.
The 4157 bulb follows the T25 wedge form factor, which refers to its trapezoidal base shape that locks into a compatible socket without a separate retaining mechanism.
As a dual-filament bulb, the 4157 operates two independent filaments within a single housing, rated at 27W for its higher-output filament and 7W for its lower-output filament.
The bulb operates on a 12-volt electrical system, consistent with standard automotive low-voltage architecture.
The Saab 9-3 uses the 4157 bulb for the daytime running light position across the 2008-2011 model years.
For the 2008 and 2009 model years, the 4157 fitment is specifically noted for vehicles equipped with HID headlamps, indicating a conditional compatibility tied to the headlamp system installed on the vehicle.
The 2010 and 2011 model years list the 4157 without an HID headlamp condition, suggesting the specification applies regardless of headlamp type for those years.
Because the 4157 is a dual-filament bulb, substituting a single-filament equivalent would not replicate the full electrical function of the original socket, as only one filament circuit would be served.