A height adjustable head restraint assembly is provided with an upright guide adapted to be mounted to a vehicle body proximate to a seat back. The guide has a cross section. A frame has a cavity with a cross section oversized relative to that of the guide to receive the guide. At least one of the guides in the frame has a plurality of projections extending to engage the other for providing guidance therebetween. A head restraint is mounted to the frame for translation along the guide. A motor is mounted to the frame for driving a threaded rod that is engaged with a fixed nut that is mounted to the guide for translating the head restraint. A pair of conductive brushes is provided on the guide and a pair of conductive contacts is mounted to the frame in electrical communication with the motor for providing power to the motor.