Description And Operation

DESCRIPTION 

Courtesy of CHRYSLER GROUP, LLC

The Comfort Seat Wheel Module (CSWM) (1) is located under the passenger seat with the seat in the full back and up position. Refer to MODULE, COMFORT REAR SEAT (CRSM), REMOVAL AND INSTALLATION .

The CSWM is a Controller Area Network - Interior High Speed (CAN-IHS) bus microcontroller providing outputs to the heated seat pads, heated steering wheel, and ventilating up to two seats. The CSWM receives commands over the CAN-IHS bus from the Body Control Module (BCM). The seat thermistor is hard wired to the CSWM.

OPERATION 

There are three levels of heat for both front seats LO, Medium, and HI. Each level will remain in the selected state for the entire ignition cycle as long as the customer does not change it. The selected heat cycle does not automatically transition to the next heat cycle based on time or temperature.

When a heated seat switch IHS data bus signal is received by the CWSM, the module energizes the selected heated seat element. The Low heat set point is about 38°C (100.4°F), and the High heat set point is about 42°C (107.6°F).

The CSWM will automatically transition the output from high to low after a maximum period of 60 minutes has elapsed. The CSWM will automatically transition the output from low to off after a maximum period of 45 minutes has elapsed.

In addition to operating the heated seat elements, the heated seat module sends LED illumination messages to the IPC. The IPC then sends the LED illumination message to the Integrated Center Stack (ICS) so that the appropriate LEDs are illuminated for any given heating level LO, Medium, or HI.

If the CSWM detects a heated seat element OPEN or SHORT circuit, it will record and store the appropriate Diagnostic Trouble Code (DTC).

Heated Seats  - The CSWM uses a Pulse Width Modulation (PWM) to provide power to the seat cushion and back heating elements. The temperature sensor thermistor is located in the seat cushion. The thermistor sensor feedbacks from each seat heating element to the CSWM to regulate the heater outputs to prevent any seat temperature to rise above set points. Seat heating has three selectable heat settings which are LO, Medium, and HI. Depending on thermistor reading, the CSWM will start the heater output by adjusting the PWM heat level according to the calibration table.

Heated Steering Wheel  - The CSWM provides power to the steering wheel heating element. The heated steering wheel is standard when the vehicle is equipped with front heated seats. During normal operation, the CSWM will switch on the power for the heated wheel only if the engine is running. The heated steering wheel temperature sensor is hardwired to the Instrument Panel Cluster (IPC) which sends that information over a Local Interface Network (LIN) bus through the Steering Column Control Module (SCCM) to the BCM. The thermistor sensor feedbacks from the steering wheel heating element via the CAN-IHS bus to the CSWM regulating the heater output to prevent the wheel temperature to rise above the maximum threshold temperature set point.

Vented Seats -  The CSWM vents the two front seats by providing variable analog voltages driving the external blowers in the seats. The seat venting has three selectable speeds for the fans LO, Medium, and HI. For seat venting, each press of the switch button will cause the seat to change venting modes. The CSWM will turn on the vented seats only with the engine running.

Driver Seat Heat Systems 

• The element consists of a cushion element connected in parallel with a back element.
• The seat cushion has a thermistor to provide feedback to the CSWM.
• The seat cushion and seat back has a thermostat to automatically open the feed to the heated seat system.
• The heated seat cushion and seat back have a thermostat to automatically open the feed to turn the heated seat system off if the temperature reaches or exceeds the operating parameters programmed to the CSWM.

Passenger Seat Heat Systems 

• The element consists of a cushion element connected in parallel with a back element.
• The seat cushion has a thermistor to provide feedback to the CSWM.
• The seat cushion and seat back has a thermostat to automatically open the feed to the heated seat system.
• The heated seat cushion and seat back have a thermostat to automatically open the feed to turn the heated seat system off if the temperature reaches or exceeds the operating parameters programmed to the CSWM.

The CSWM is diagnosed using a diagnostic scan tool. If the module detects a heated seat element OPEN or SHORT circuit, the system will turn off and it will record and store the appropriate Diagnostic Trouble Code (DTC). Refer to DTC INDEX (1 OF 3) and/or DTC INDEX (2 OF 3) and/or DTC INDEX (3 OF 3) .