A vehicle seat having a first temperature control unit and a second temperature control unit. Each control unit has power-input terminals for receiving power from a vehicle electrical power system and power-output terminals. The first control unit has a logic part for comparing received temperature selection and temperature measurement values along with a first pulse generator connected to a first output terminal of the logic part and a second pulse generator connected to a second output terminal of the logic part as well as a first switch unit coupled to the first pulse generator. The second temperature control unit includes a second switch unit coupled to the second pulse generator. First and second heating elements are coupled to the temperate control units. An occupant switch is coupled to the first temperate control unit. A first temperature sensor monitors the thermal output of the first heating element.