The Plymouth PB250 front and rear turn signal bulbs both utilize a 1157 size bulb for proper operation. The replacement chart covers vehicle production spanning 1981 to 1983.
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 across all listed turn signal positions on the Plymouth PB250, covering both front and rear applications for the 1981-1983 model years.
The 1157 is a dual-filament bulb, meaning it contains two separate filaments within a single envelope. One filament operates at 21W and the other at 5W, allowing it to serve both a high-intensity signaling function and a lower-intensity running or parking light function simultaneously.
The 1157 uses a BAY15d bayonet base, which is an offset twin-pin mount. The two pins are positioned at different heights on the base, a design that prevents incorrect insertion and ensures the filaments align with the correct circuits in the socket.
The 1157 is rated at 12 volts, consistent with the standard electrical system voltage found in conventional passenger and light commercial vehicles of this era.
The 1157 conforms to ANSI standards and carries recognition in both the United States and Canada, indicating it meets a shared North American specification for bulb performance and physical form.
Because the Plymouth PB250 uses the same 1157 bulb for both the front and rear turn signals, a single bulb type serves all four turn signal positions on the vehicle across the 1981-1983 model years.
The BAY15d base of the 1157 is not interchangeable with single-filament bayonet bases such as the BA15s, which shares a similar physical profile but lacks the second pin offset. Substituting a single-filament bulb in a dual-filament socket would result in incomplete circuit function.