The Audi 5000 front turn signal requires a 1157 bulb size while the rear turn signal uses either P21W or 1073 bulb sizes. The replacement chart covers 1978 to 1987 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Audi 5000 front turn signal position uses the 1157 bulb across all model years from 1978-1987, reflecting a consistent fitment choice for that position throughout the vehicle's production span in these specifications.
The 1157 is an ANSI-standard dual-filament bulb rated at 12V with a 21W main filament and a 5W secondary filament, mounted on a BAY15d bayonet base. The dual-filament design allows a single bulb to serve both a steady running light function and a brighter flashing signal function.
The rear turn signal position on the Audi 5000 uses the P21W bulb for most years covered, specifically 1978 and 1980-1987.
The P21W is an ECE-standard single-filament bulb rated at 12V, 21W, fitted with a BA15s bayonet base. Its ECE classification reflects European and international regulatory origins, which aligns with the Audi 5000's European market heritage.
The 1979 Audi 5000 rear turn signal is specified with the 1073 bulb rather than the P21W used in surrounding years, making it the sole year in these specifications to carry that designation for that position.
The 1073 is an ANSI-standard single-filament bulb rated at 12V and 13W, also using a BA15s bayonet base. It is described as a lower-wattage variant of the 1156 bulb type.
Although the 1073 and P21W share the same BA15s bayonet base, their wattage ratings differ at 13W and 21W respectively. This difference means the two bulb types are not directly interchangeable without potential effects on circuit load and signal brightness.
The front 1157 uses a BAY15d base, while both the P21W and 1073 use a BA15s base. The BAY15d base features offset locating pins to prevent incorrect installation of a single-filament bulb in a dual-filament socket, making cross-position substitution physically incompatible.
The shift between ANSI and ECE bulb standards across the two turn signal positions on the Audi 5000 reflects a mixed-market specification, where the front position follows North American standards and the rear position predominantly follows European standards.