Audi 4000 License Plate Bulb Size

The Audi 4000 license plate light requires a 3893 bulb size for proper illumination of the rear registration area. Data for the specific component covers the span from 1980 through 1987.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1980-1987	3893

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base, specialty application. 12V.	3893

Other Locations

Additional Notes

The Audi 4000 uses the 3893 bulb for its license plate lighting across all model years represented in the specifications, spanning 1980-1987.
The 3893 is an ANSI-standardized bulb, meaning it conforms to a defined set of electrical and physical standards recognized across the United States and Canada.
This bulb operates on a 12-volt electrical system, which is consistent with standard automotive low-voltage architecture.
The 3893 features a dual-filament design, meaning it contains two separate filaments within a single bulb envelope, each capable of operating independently.
It uses a BAY15d bayonet base, a two-pin offset bayonet mount where the two pins are positioned at different heights to ensure the bulb can only be seated in one orientation, preventing incorrect installation.
The BAY15d base type is classified as a specialty application fitment, indicating it is not among the most broadly distributed base types and may have a narrower range of compatible replacement options.
Because the BAY15d base uses offset pins, substitution with a standard BAY15s or BAY15d variant that does not match the pin offset would result in an incompatible fit.