The Volkswagen Vanagon brake light uses P21/5W and P21W bulb sizes for the rear lighting system. Data for the specified vehicle covers the range from 1980 through 1991.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Volkswagen Vanagon uses two distinct brake bulb types across its production run: the dual-filament P21/5W for model years 1986-1991 and the single-filament P21W for model years 1980-1985.
The P21/5W is an ECE-standard dual-filament bulb rated at 12V with a 21W main filament and a 5W secondary filament, mounted on a BAY15d bayonet base.
The BAY15d base on the P21/5W features offset pins, which physically prevents incorrect installation of a single-filament bulb in its place.
The P21W is an ECE-standard single-filament bulb rated at 12V, 21W, and uses a BA15s bayonet base with symmetrically placed pins.
Because the P21/5W and P21W use different bayonet bases, BAY15d and BA15s respectively, the two types are not interchangeable in the Volkswagen Vanagon brake light housings.
The center high mount stop light on the Vanagon is specified for model years 1986-1991 and uses the 12961 bulb, a Philips part number designation for a T10 miniature wedge bulb.
The 12961 T10 wedge bulb operates at 12V, 5W, and seats into a W2.1x9.5d wedge base, which differs entirely from the bayonet bases used in the main brake light positions.
The P21/5W and P21W designations follow ECE (Economic Commission for Europe) naming conventions, indicating these bulbs were specified to European and international signalling standards rather than North American SAE standards.