The new Golf VI is first to combine ECE-compliant high beam and DRL functions in one single reflector with a single light bulb. The lamp uses the new H15B double-filament 55/15w halogen bulb, which allows headlamp and car manufacturers to add ECE R87-compliant DRLs — mandatory in the E.U. from 2012 — to their vehicles without a significant design change.
The H15B is the descendent of the DFCS (Double Filament for Complex Shape reflectors), conceived as an internationally-approved, high-precision, performance-optimized successor to the 1971-vintage H4 double-filament halogen headlight bulb. However, American vehicle and headlamp makers could not be convinced of its technical merit; they proceeded to refine the American 9007 bulb into the H13, and so the DFCS project as a new high/low beam headlamp light source faltered.
A variant form of DFCS, however, evolved to become the H15 and H15B. The standard and “B” bulbs, both approved in ECE R37, are identical from the mounting plane forward. The socket details, however, differ markedly. The H15B greatly eases the task of changing a failed bulb; the installer need merely grasp and rotate the bulb about 45°. There is no need to disconnect or reconnect sockets or wires, nor to install the bulb in a holder (cf Bulb Removal Survey at www.DrivingVisionNews.com)