Volkswagen Dasher Back Up Light Bulb Size

The Volkswagen Dasher back up light utilizes P21W and 1156 bulb sizes for the rear illumination system. Data for the specific components covers the period from 1974 through 1981.

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
1974-1981	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

Other Locations

Additional Notes

The Volkswagen Dasher uses the 1156 bulb for its back up light across all listed model years, spanning 1974-1981.
The 1156 is an ANSI-standardized bulb type, meaning its specifications are governed by a recognized North American standard applicable in both the United States and Canada.
The 1156 operates on a 12-volt electrical system and draws 21 watts, which is consistent with standard automotive reverse lighting applications.
The 1156 is a single-filament bulb, meaning it serves one lighting function only, as opposed to dual-filament types that handle two functions such as braking and running light simultaneously.
The 1156 uses a BA15s bayonet base, where "BA15s" denotes a bayonet-style mount with a 15mm base width and a single contact pin, distinguishing it from the BA15d variant, which carries two contact pins for dual-filament use.
The single-contact BA15s base of the 1156 is not interchangeable with dual-contact bayonet bases, so substituting a dual-filament bulb such as the 1157, which shares a similar physical profile but uses a BA15d base, would not be a compatible replacement in the Dasher's back up light socket.