The Saab 9-3X uses a 12961 bulb size for the front side marker and a P21/5W bulb size for the rear side marker. The replacement chart covers 2010 to 2011 vehicle production 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 Saab 9-3X uses two distinct bulb types across its front and rear side marker positions for the 2010-2011 model years.
The front side marker on the Saab 9-3X uses the 12961, a Philips part number designating a miniature wedge bulb of the T10 type with a W2.1x9.5d base, rated at 12V and 5W.
The T10 wedge base is a push-fit design that seats directly into a socket without rotation, which is characteristic of low-wattage indicator and marker applications.
The rear side marker uses the P21/5W, an ECE-standard dual-filament bulb rated at 12V with two wattage outputs of 21W and 5W, housed in a BAY15d bayonet base.
The BAY15d base is an offset twin-contact bayonet fitting, where the two pins are positioned at different heights to prevent incorrect installation of the bulb.
The dual-filament nature of the P21/5W means it serves two independent lighting functions from a single bulb, with the 21W filament typically assigned to brighter signalling and the 5W filament to a lower-intensity function.
The front and rear side marker positions are not interchangeable on the 9-3X, as the T10 wedge base and the BAY15d bayonet base are physically incompatible with each other's sockets.
The wattage difference between the two bulb types is substantial, with the P21/5W rear bulb drawing significantly more power at its primary filament than the 5W front marker bulb.