Audi 90 License Plate Bulb Size

Additional Notes

• The 3893 bulb is the sole license plate bulb type specified for the Audi 90 across all listed model years.
• The 3893 is an ANSI-standardized bulb recognized in both the United States and Canada, meaning it conforms to a defined set of electrical and physical standards shared across those markets.
• The 3893 operates on a 12-volt electrical system, which is the standard automotive voltage found in most passenger vehicles.
• Despite being listed for a license plate position, the 3893 is a dual-filament bulb, meaning it contains two separate filaments within a single envelope, a construction more commonly associated with stop/tail or turn signal applications.
• The 3893 uses a BAY15d bayonet base, which is an offset twin-pin base. The offset pin arrangement is a deliberate anti-misalignment feature, preventing the bulb from being seated in an incorrect rotational position.
• The BAY15d base is not universally interchangeable with other bayonet base types such as the BA15s (single-contact) or BA15d (non-offset twin-pin), and substituting those types would result in incorrect fitment for the Audi 90 license plate socket.
• The 3893 is classified as a specialty application bulb, indicating it is not among the most broadly distributed standard replacement types and may require sourcing from suppliers carrying a wider bulb inventory.
• The Audi 90 used the same 3893 bulb specification without variation across the 1988-1995 model years represented in the data.