The Chevrolet Laguna front and rear turn signal bulbs both utilize a 1157 size bulb for proper operation. The replacement chart covers vehicle production spanning 1973 to 1976.
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 Chevrolet Laguna across both front and rear turn signal positions for the 1973-1976 model years.
The 1157 is an ANSI-standardized bulb, meaning its physical and electrical characteristics conform to a defined North American specification recognized in both the United States and Canada.
The 1157 is a dual-filament bulb, which means it contains two separate filaments within a single envelope, allowing it to serve two distinct lighting functions from one unit.
The 1157 operates on a 12-volt electrical system, consistent with standard automotive electrical architecture of the era.
Its two filaments are rated at 21 watts and 5 watts respectively, with the higher-wattage filament typically serving the active turn signal function and the lower-wattage filament serving a parking or running light function.
The 1157 uses a BAY15d bayonet base, a two-pin offset base design that physically prevents incorrect insertion by positioning the two pins at different heights along the base.
Because the same 1157 bulb is specified for both the front and rear turn signal positions across all four model years, the Laguna uses a single bulb type for all four turn signal sockets.
The BAY15d base is not interchangeable with single-filament bayonet bases such as the BA15s, as the dual-pin offset configuration is specific to dual-filament applications.