Porsche 912 front turn signal bulbs utilize either 1157 or 1156 size, while rear turn signal bulbs use 1156 size specifications. The replacement chart covers 1965 through 1976 production years with corresponding bulb size data.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 1156 bulb is the most frequently specified type across the Porsche 912 turn signal data, appearing in all rear turn signal positions for model years 1965-1976 and in all front turn signal positions for model years 1965-1968.
The 1156 is a single-filament bulb operating at 12V with a 21W output and uses a BA15s bayonet base, making it suited to circuits requiring only one function, such as a dedicated turn signal.
The 1157 bulb appears exclusively in the front turn signal position for the 1969 and 1976 Porsche 912 model years.
The 1157 is a dual-filament bulb rated at 12V with a 21W/5W output and uses a BAY15d bayonet base, which physically differs from the BA15s base of the 1156.
The BAY15d base of the 1157 has offset locating pins, while the BA15s base of the 1156 has a single pin, meaning the two bulb types are not interchangeable despite their similar physical appearance.
Both the 1156 and 1157 are ANSI-standardized bulb types recognized in the United States and Canada.
The front turn signal position on the Porsche 912 is the only location where a specification change between the 1156 and 1157 occurs across the listed model years.
The rear turn signal position on the Porsche 912 uses the single-filament 1156 across all listed model years, indicating a consistent single-function circuit at that location throughout the production span covered by these specifications.