GM Service Manual Online
For 1990-2009 cars only

Heated Seat Operation

Battery positive voltage is supplied to the heated seat module from the HTD SEATS/BCK UP and HTD/SEAT fuses located in the underhood fuse block. When commanded ON, the heated seat module uses this voltage to heat the seat heating elements. The heated seat module and the seat heating elements are grounded through the module ground circuit to G301 and G302.

Each time the heated seat switch is pressed, B+ is supplied to the heated seat module through the heated seat signal circuit. The module counts these inputs to determine what level of heat the vehicle operator is commanding. In response to these switch signals, the heated seat control module sends a B+ signal to illuminate the appropriate heated seat indicator. The heated seat module then closes it's contacts and applies B+ through the heated seat element supply voltage circuit to the seat heating elements. When the thermistor inside the seat cushion reaches a certain resistance, the control module open and close the supply voltage in order to maintain that heat level.