The Citroen DS21 Pallas uses a 1157 bulb size for both front and rear turn signal applications. The replacement chart covers 1969 to 1972 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 1157 is the sole bulb type specified for the Citroen DS21 Pallas across all listed turn signal positions and model years.
The 1157 is an ANSI-standardized bulb, meaning it conforms to a North American (US and Canada) specification rather than a European automotive standard.
The 1157 is a dual-filament bulb, which allows it to serve two distinct lighting functions within a single housing, typically a higher-wattage filament for signaling and a lower-wattage filament for a secondary function such as running or parking light.
The bulb operates at 12 volts with a wattage rating of 21W on the primary filament and 5W on the secondary filament.
The 1157 uses a BAY15d bayonet base, a two-pin offset bayonet mount that is mechanically keyed to prevent incorrect filament orientation during installation.
The BAY15d base designation indicates that the two pins are offset at different heights, a design that prevents a single-filament bulb with a similar base from being seated in its place.
The front and rear turn signal positions on the DS21 Pallas share the same 1157 bulb specification across the 1969-1972 model years covered in the data.