The Citroen D Special uses 1157 bulb size for both front and rear turn signal applications. The replacement chart covers 1970 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 D Special across all listed positions and years, covering both front and rear turn signals from 1970-1972.
The 1157 is a dual-filament bulb, meaning it contains two separate filaments within a single envelope, allowing it to serve two distinct lighting functions at different wattages.
The 1157 operates on a 12-volt electrical system and draws 21 watts on its primary filament and 5 watts on its secondary filament, reflecting its dual-function design.
The 1157 uses a BAY15d bayonet base, a two-pin offset base type where the two pins are positioned at different heights to ensure the bulb can only be seated in one rotational orientation.
The 1157 conforms to ANSI standards and is classified as a US and Canada specification, indicating it follows North American automotive lighting norms rather than European ECE standards.
Because the same 1157 bulb is specified for both the front and rear turn signal positions on the D Special, the two positions share full bulb interchangeability with each other.