Peugeot 405 front and rear turn signal bulbs utilize a P21W size. The replacement chart covers 1989 to 1991 model years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The P21W is the sole bulb type specified for the Peugeot 405 across all listed turn signal positions and model years.
The P21W operates at 12 volts with a 21-watt output, classifying it as a single-filament bulb intended for signalling functions rather than illumination.
The P21W uses a BA15s bayonet base, where "BA" denotes a bayonet cap fitting, "15" refers to the 15mm base width, and the lowercase "s" indicates a single contact at the base.
The BA15s single-contact base distinguishes the P21W from the visually similar P21/5W, which uses a BA15d dual-contact base and carries a secondary filament for combined stop and tail functions. The two are not interchangeable.
The P21W conforms to ECE regulations, a standard recognized across Europe and numerous other markets worldwide.
Both the front and rear turn signal positions on the Peugeot 405 share the same P21W specification across the 1989-1991 model years covered in the data.