The Porsche Cayenne side marker requires a unique bulb size of 12961 for the lighting components. Data for the specific bulb requirements covers the range from 2018 to 2018.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Porsche Cayenne uses the 12961 bulb for the front side marker position across the 2003-2018 model years, with the sole exception of 2007, which has no front side marker entry in the specifications.
The 12961 is a Philips part number designating a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12V and 5W.
The T10 wedge base is a push-in fitment, meaning the bulb is held in place by friction rather than a locking twist or bayonet mechanism.
At 5W, the 12961 is a low-wattage bulb consistent with side marker applications, where output requirements are lower than those of primary signalling lamps such as brake or turn signal bulbs.
The rear side marker position on the Porsche Cayenne uses the P21/4W bulb for the 2003-2006 model years.
The P21/4W is an ECE-standard dual-filament bulb with a BAZ15d offset bayonet base, rated at 12V with filaments drawing 21W and 4W respectively.
The BAZ15d base features two pins set at different heights, a design that prevents incorrect installation by ensuring the bulb can only be seated in one orientation.
The dual-filament construction of the P21/4W allows a single bulb to serve two distinct lighting functions, with the 4W filament typically assigned to the lower-intensity marker role and the 21W filament to a brighter signalling function.
The front and rear side marker positions on the Porsche Cayenne use different bulb types and bases, making the 12961 and P21/4W non-interchangeable between those positions.
The W2.1x9.5d wedge base of the 12961 and the BAZ15d bayonet base of the P21/4W are physically incompatible socket types, so substitution between the two requires a socket adapter or housing modification.