Heated and Cooled Seat Switches / HVAC Control Module
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
The heated and cooled seat system is controlled through 3 different switch inputs of the HVAC control module. When one of the switches is pressed, the HVAC control module sends a serial data message to the MSM indicating the switch input. In response to this message, the MSM sends a pulse width modulation (PWM) signal through the heated/cool seat mode signal circuit to the CCSM indicating the heated or cooled seat request. During heated or cooled seat operation the HVAC control module displays the switch symbol of the active operating mode and the temperature level bars on the climate control display determined by a serial data message from the MSM.