Abstract: A filler unit for carrying a device, for example to actuate toggle switches, for controlling lighting and audio accessories of a vehicle, such as motorcycles, all-terrain vehicles and the like, which comprises a master cylinder normally mounted on a wheel-steering member, such as handlebars. The master cylinder, while performing its normal functions as a brake control, has a support casing affixed to the wheel-steering member in close proximity to an operator's hand. The filler unit's housing is positioned on the master cylinder support casing in vertical alignment therewith, thereby resulting in an integrated “sandwich” structure. The switches of the control device are located on the front portion of the housing for convenient operation, thereby achieving a compact and readily accessible configuration, which is also cosmetically compatible with the streamlined look of the vehicle.