A motor assembly for a window lift mechanism has a motor and a gearbox. The motor includes a stator having a metal housing, and a rotor with a commutator, rotatably received in the housing. An end cap assembly is connected to the housing. The end cap assembly includes a plurality of brushes making sliding contact with the commutator, a plurality of connecting pieces for connecting an external power source, inductors connected between the brushes and the connecting pieces, and shielding layers cladding the inductors and electrically connected to the housing.