Peugeot 504 front and rear side marker bulbs utilize a 12821 bulb size for both locations. The replacement chart covers vehicle production spanning 1969 to 1983.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Peugeot 504 uses the 12821 bulb for both its front and rear side marker positions across all model years covered in the specifications, spanning 1969-1983.
The 12821 is a Philips part number designating a miniature wedge bulb in the T10 form factor, operating at 12 volts and rated at 5 watts.
The T10 designation refers to a tubular bulb with a width of approximately 10 millimeters, a standard sizing classification used across many miniature automotive lighting applications.
The 12821 uses a W2.1x9.5d wedge base, which is a pushfit connector type that requires no separate socket locking mechanism, relying instead on the tension of the housing to retain the bulb.
The W2.1x9.5d base is the standard wedge base found on T10 bulbs, and it is not interchangeable with bayonet or festoon base types without a socket adapter.
At 5 watts on a 12-volt circuit, the 12821 draws approximately 0.42 amperes, which is consistent with low-current marker light applications rather than high-intensity functions such as braking or headlighting.
The uniform fitment of a single bulb type across both front and rear side marker positions on the Peugeot 504 means the same part serves four distinct lighting points on the vehicle.
Because the 12821 is a Philips-designated part number, equivalent bulbs from other manufacturers are cross-referenced by their shared T10 W2.1x9.5d base and 12V/5W rating rather than by the Philips number itself.