STS AWD V6-3.6L (2007)
Seat Heater: Description and Operation
Heated/Vented Seat Description and Operation
Heated/Vented Seat Description and Operation
The heated/vented seat system consists of the following components:
* Heated/Vented seat switch
* Climate control seat module
* HVAC control module
* Memory seat module (MSM)
* Seat cushion heater element
* Seat back heater element
* Temperature sensor
* Seat cushion blower motor
* Seat back blower motor
* RF HTD ST/S-BAND Fuse 20 A
* IGN 3 Fuse 10 A
* DPM Fuse 10 A
Helpful Hints
* The memory seat module (MSM) is also referenced as the driver position module (DPM) for this vehicle.
* The vented seat is also referenced as the cooled seat for this vehicle.
* The climate control seat module, located under the front passenger seat cushion, controls the heated and vented seat operations for both the driver
and front passenger seats.
Power and Ground
Battery positive voltage is supplied to the climate control seat module from the IGN 3 Fuse located in the left rear fuse block. This voltage is used to
power up the climate control seat module allowing the heated seats to operate only when the ignition switch is in the ON position. Battery positive
voltage is also supplied at all times to the climate control seat module from the RF HTD ST/S-BAND fuse located in the right rear fuse block. This
voltage is used by the module to supply power to the seat heating elements and is wired directly to the front passenger vented seat blower motors. Battery
positive voltage is supplied directly to the driver vented seat blower motors from the DPM fuse located in the left rear fuse block. Ground is provided to
the module through the module ground circuit and G307.
Heated/Vented Seat Switch
Separate heated and vented seat switches located in the HVAC control module control the driver and passenger heated/vented seats. When a heated or
vented seat switch is pressed, the HVAC control module sends a GMLAN message via the serial data line to the MSM indicating the heated or vented
seat command. In response to this signal, the MSM sends a low side PWM signal through the appropriate driver or passenger PWM serial data circuit to
the climate control seat module. The module then activates the appropriate heated or vented seat mode. The MSM then sends a GMLAN message back
to the HVAC module to illuminate the appropriate temperature indicator.
Heated Seat Operation
When the ignition is turned to the ON position, the heated/vented seats will initialize in the OFF state. When the heated seat switch is pressed once, the
climate control seat module applies battery positive voltage through the heated seat element supply voltage circuit to the seat cushion and seat back
heating elements, initially setting the seat temperature to high heat. Then with each additional activation of the switch, the climate control seat module
will cycle the temperature setting to MED, LOW, and OFF. The module will also turn off the heated seat function whenever the ignition switch is turned
to the OFF position.
Temperature Regulation
The heated seat system is designed to warm the seat cushion and seat back to approximately 42°C (107.6°F) when in the high heat position, 39.5°C
(103.1°F) when in the medium heat position, and 37°C (98.6°F) when in the low heat position. The climate control 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, its resistance changes as the temperature of the seat changes. When the temperature sensor resistance indicates to the climate
control seat module that the seat has reached the desired temperature, the module turns off the element supply voltage to the seat heating elements. The
module will then cycle the element supply voltage on and off in order to maintain the desired temperature.
Vented Seat Modes of Operation
When the ventilation seat system is active, it is designed to draw cabin air around and away from the occupant through small holes in the seat cushion
and seat back covers, through channels in the foam pad, and then through the blower motor exhausting the waste air under the seat cushion.
