Description And Operation
DESCRIPTION
| 1 - CSWM |
The Comfort Seat and Wheel Module (CSWM) is located below steering column and the Power Inverter Module (PIM) (if equipped) in the instrument panel. It has a multiple wire harness connectors (Controller Area Network-Interior High Speed/CAN-IHS, Power, Front Heat, Front Vent and Heated Steering Wheel connections) and a push pin style retainer that secures it to the seat pan.
The CSWM provides output signals on the CAN-IHS bus as well as receives CAN-IHS bus signals from the various modules. The seat thermistor is hard wired to the CSWM.
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 two selectable heat settings which are HI and LO. 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 sends that information over a Local Interface Network (LIN) bus through the Steering Column Control Module (SCCM) to the Body Control Module (BCM). The thermistor sensor feedbacks from the steering wheel heating element via the CAN Internal High Speed (IHS) bus to the CSWM regulating the heater output to prevent the wheel temperature to rise above the maximum threshold temperature set point.
OPERATION
Heated Systems Modules:
- The CSWM controls the heated seat system.
- The Steering Column Control Module (SCCM) is the interface (Power feed and return) between the heated steering wheel element and the vehicle.
- The Steering Wheel Switch (SWS) converts hard wired sense and return information into a LIN bus message and sends this message to the BCM.
- The BCM gates messages between the CAN-Chassis (CAN-C) bus and the CAN-IHS bus. Additionally, the BCM provides vehicle configuration data to the CSWM.
Refer to DESCRIPTION AND OPERATION, STEERING WHEEL for heated steering wheel information.
Heated Seats:
- The heated seat system operates on battery current received through fused ignition switch output (RUN) circuits and will only operate when the engine is running.
- The CSWM directly provides power to the seat heating elements in the seat cushions and seat backs for seat heating.
- The driver seat heat system and passenger seat heat system each consist of a cushion element connected in parallel with a back element.
- A thermistor sensor feedback from each seat heating element to the CSWM is used to regulate the heater outputs to prevent any seats temperature from rising above the set points. If a seat temperature exceeds the set point the CSWM automatically disables the system.
- The high level cutoff value range is from 50° - 60° C (120° - 140° F) in increments of 1 degrees Fahrenheit. The typical value is 54° C (129° F).
- The low level cutoff value range is from 50° - 60° C (120° - 140° F) in increments of 1 degrees Fahrenheit. The typical value is 55° C (131° F).
- The CSWM will also turn off the heated seat elements if an open or short in the heating element circuit is detected.
- Each time a heated seat request signal is received by the CSWM, the heated seat output will cycle from Off to High, High to Low and Low to Off. (i.e the first press cycles from Off to High, the next press cycles from High to Low and the next press cycles from Low to Off.)
- When the CSWM receives the actuation request, the CSWM activates the heating element output at the high level and transmits a message on the CAN-IHS bus to indicate the current output state is high.
- The CSWM automatically transitions the output from high to low after a maximum period of 60 minutes has elapsed and transmits a message on the CAN-IHS bus to indicate the current output state is low.
- The CSWM automatically transitions the output from low to off after a maximum period of 45 minutes has elapsed and transmits a message on the CAN-IHS bus to indicate the current output state is off.
When pressing the heated seat switch:
- A CAN-IHS bus message request is generated.
- The CSWM receives the "Heated Seat request" from the CAN-IHS bus.
- The CSWM broadcasts a confirmation of actuation message over the CAN-IHS bus.
- The CSWM energizes an integral solid-state relay, which supplies Pulse Width Modulated (PWM) current to the heating elements of the designated seat(s).
- The CSWM monitors the seat temperature.