Plymouth Sapporo front turn signal bulbs measure 1157 in size, while rear turn signal bulbs measure 1156, with each bulb type serving distinct lighting functions on the vehicle. The replacement chart covers 1978 to 1983 model years and details bulb size specifications across the production range.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Plymouth Sapporo uses the 1157 bulb for the front turn signal across all model years from 1978-1983.
The 1157 is a dual-filament bulb operating at 12V with a 21W/5W output, meaning it draws 21 watts on the high-intensity filament and 5 watts on the low-intensity filament, allowing it to serve two lighting functions within a single housing.
The 1157 uses a BAY15d bayonet base, which features two offset pins at different heights to prevent incorrect installation of the bulb.
The rear turn signal on the Plymouth Sapporo takes the 1156 bulb across all model years from 1978-1983.
The 1156 is a single-filament bulb rated at 12V and 21W, dedicated to one lighting function rather than the dual-purpose role of the 1157.
The 1156 uses a BA15s bayonet base, which has two pins at equal heights, making it physically distinct from the BAY15d base of the 1157.
Both the 1157 and 1156 are ANSI-standardized bulbs recognized in the United States and Canada, meaning their electrical and physical specifications conform to a defined industry standard.
Although the 1156 and 1157 share a similar 15mm bayonet base style, the pin offset difference between BA15s and BAY15d means the two bulbs are not interchangeable with each other.