Volkswagen Squareback front turn signal bulbs measure 1157 in size, while rear turn signal bulbs measure 1156 in size. The replacement chart covers vehicle production spanning 1969 to 1973 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 Volkswagen Squareback uses two distinct bulb types across its turn signal positions: the 1157 at the front and the 1156 at the rear, a split that holds consistent across the 1969-1973 model years covered in these specifications.
The 1157 is a dual-filament bulb, meaning it carries two separate filaments within a single envelope, allowing it to serve more than one lighting function from the same socket.
The 1157 operates on a 12-volt circuit 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 that physically prevents incorrect insertion, as the two pins are positioned at different heights on the base.
The 1156 is a single-filament bulb rated at 12 volts and 21 watts, dedicated to a single lighting function at the rear turn signal position.
The 1156 uses a BA15s bayonet base, a single-pin design that is not interchangeable with the BAY15d base of the 1157, despite the two bulbs sharing a similar overall form.
Both the 1157 and 1156 conform to ANSI standards and are specified for use in the United States and Canada, indicating they meet the standardized electrical and photometric requirements for those markets.
Because the 1157 and 1156 share a similar physical profile but differ in base configuration and filament count, substituting one for the other is not possible without a socket mismatch.