Volkswagen Transporter front turn signal bulbs measure 1157 in size, while rear turn signal bulbs measure 1156 in size. The replacement chart covers vehicle production spanning 1968 to 1979 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 Volkswagen Transporter uses the 1157 bulb for the front turn signal across the 1968-1979 model years.
The 1157 is a dual-filament bulb operating at 12V with a 21W/5W output and a BAY15d bayonet base, conforming to ANSI standards used in the US and Canada.
The dual-filament design of the 1157 allows it to serve two lighting functions within a single housing, with the higher 21W filament handling the turn signal function and the lower 5W filament serving a secondary role such as a parking light.
The rear turn signal on the Volkswagen Transporter uses the 1156 bulb across the same 1968-1979 model years.
The 1156 is a single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base, and also conforms to ANSI standards for the US and Canadian markets.
The BA15s base of the 1156 and the BAY15d base of the 1157 are physically distinct. The BAY15d base features two offset pins to prevent incorrect installation, while the BA15s base has two pins at the same height. These two bulbs are not interchangeable despite their similar appearance.
Both the 1156 and 1157 share the same 15mm bayonet base collar width, which is the source of potential confusion when selecting replacements. The pin offset on the BAY15d is the critical differentiating factor.
The consistent use of the 1157 at the front and the 1156 at the rear across all listed model years reflects a deliberate split between dual-filament and single-filament applications within the same vehicle's lighting system.