The Audi Cabriolet front turn signal requires a P21/5W bulb size while the rear turn signal uses a P21W bulb size. The replacement chart covers 1994 to 1998 model 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 Cabriolet uses the P21/5W bulb in the front turn signal position across all model years from 1994-1998.
The P21/5W is a dual-filament bulb rated at 12V with a 21W primary filament and a 5W secondary filament, which allows a single bulb to serve two lighting functions simultaneously.
The P21/5W uses a BAY15d bayonet base, an offset two-pin fitting designed to prevent incorrect installation by positioning its two pins at different heights.
The rear turn signal position on the Audi Cabriolet uses the P21W bulb across all model years from 1994-1998.
The P21W is a single-filament bulb rated at 12V and 21W, dedicated solely to one lighting function rather than sharing duties across two filaments.
The P21W uses a BA15s bayonet base, a single-pin fitting that differs from the BAY15d base found on the front turn signal bulb. The two bulbs are not interchangeable despite sharing the same 21W output on their primary filaments.
Both the P21/5W and P21W conform to ECE standards, a regulatory framework recognized across Europe and numerous other markets worldwide.
The differing base types between the front and rear bulbs serve as a mechanical safeguard, as the physical incompatibility of the BA15s and BAY15d fittings prevents a rear-position P21W from being seated into a front-position socket designed for the P21/5W.