Seat Temperature Element: Description and Operation

Heated Seats Description and Operation

The front heated seat system consists of the following components.

* Left heated seat switch
* Right heated seat switch
* Heated seat module
* Left seat cushion heater element
* Left seat back heater element
* Left seat temperature sensor
* Right seat cushion heater element
* Right seat back heater element
* Right seat temperature sensor
* Climate Control Panel (CCP)
* HTD/SEAT 10 A

Power and Ground

Battery positive voltage is supplied at all times to the heated seat module from the HTD/SEAT fuse located in the I/P fuse block. This voltage is used by the module to supply power to the seat heating elements. The module is grounded through the module ground circuit and G301.

Heated Seat Operation

The driver and passenger heated seats are controlled by a single heated seat module that is located under the driver seat cushion. Both heated seats are controlled by separate heated seat switches that are located in the climate control panel (CCP). When a heated seat switch is pressed, the CCP sends a GMLAN message via the serial data line to the heated seat module indicating the heated seat command. In response to this signal, the heated seat module then applies battery positive voltage through the element supply voltage circuit to the appropriate seat heating elements. The heated seat module then sends a GMLAN message back to the CCP to either illuminate or turn off the appropriate temperature indicator.

Temperature Regulation

When the ignition is turned to the ON position, the heated seats will initialize in the OFF state. With each activation of the heated seat switch, the heated seat module will cycle the temperature setting in the following manner: HIGH, LOW, and OFF.

The heated seat module monitors the seat temperature through the temperature sensor signal circuit and the temperature sensor (thermistor) that is located in the seat cushion. The temperature sensor is a variable resistor, it's resistance changes as the temperature of the seat changes. When the temperature sensor resistance indicates to the heated seat module that the seat has reached the desired temperature, the module opens the ground path of the seat heating elements through the heated seat element control circuit. The module will then cycle the element control circuit open and closed in order to maintain the desired temperature.

Load Management

The load-shed operation is a means of reducing vehicle electrical loads during a low voltage or low battery state of charge (SOC) condition. During certain load-shed conditions, all heated seat functions will be disabled. Refer to Electrical Power Management Description and Operation (Electrical Power Management).