The invention relates to an electric control device for an automobile, that comprises a touch-surface sensor using pressure-sensitive resistors and to be assembled with a holder (3) having a recessed or protruding three-dimensional surface, characterized in that the touch-surface (1) of the sensor is shaped so that, at the assembled state, a portion of at least the shaped touch-surfaces (1) meet each other while conforming to the shape of said three-dimensional surface (4) in order to define an essentially continuous touch-surface (1).