The 1157 is the sole bulb type specified for the Yugo GVL across all listed turn signal positions and model years.
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 at 12 volts and draws 21 watts on its primary filament and 5 watts on its secondary filament, reflecting its dual-purpose role in automotive lighting circuits.
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.
The 1157 conforms to ANSI standards and is rated for use in the United States and Canada, indicating standardized electrical and physical tolerances across manufacturers.
Both the front and rear turn signal positions on the Yugo GVL share the same 1157 bulb specification for the 1988-1989 model years.
Because the front and rear positions use an identical bulb type, a single replacement part satisfies both fitment requirements on this vehicle.
The BAY15d base is not interchangeable with single-filament bayonet bases such as the BA15s, as the offset pin configuration and dual-filament wiring differ between the two types.