Description And Operation
DESCRIPTION
The heated seat system consists of the following components:
| 1. | Refer to BODY CONTROL MODULE (BCM) . |
| 2. | Refer to UCONNECT® TOUCH SCREEN (if equipped). |
| 3. | Refer to INTEGRATED CENTER STACK (ICS) MODULE . |
| 1. | Refer to COMFORT SEAT AND WHEEL MODULE (CSWM) . |
| 2. | Refer to HEATED SEAT ELEMENTS (Seat Back and Seat Bottom). |
| 3. | Refer to HEATED AND VENTILATED SEAT BLOWER MOTORS . |
| - | Refer to VENTILATED SEAT PLENUMS . |
OPERATION
When the occupants of the front seats request the activation of the heated seats (two heating levels) or the steering wheel through the control panel, the command is sent via Local Interface Network (LIN) bus to the BCM. The BCM translates the command received and sends it via Controller Area Network - Interior High Speed (CAN-IHS) to the CSWM. The CSWM supplies the heater pads placed on the front seat backrests and cushions and will receive the signal directly from the two temperature sensors (one per seat) in the cushions, to learn the temperature of the seats and use the correct strategies for supplying the heater pads.
The CSWM monitors the operation of the system and will generate the appropriate Diagnostic Trouble Codes (DTC) in the event of failure.
When operating the heated seat switch, one of three switch positions can be selected: OFF, LOW, or HIGH. The CSWM can provide three levels of power to the heating elements for the HIGH setting. These power levels are changed by modulating the pulse width of the positive side of the circuit. The strategy used by the CSWM is to operate the heating element at the highest pulse-width until the target time or temperature for the pulse width is met. The CSWM then reduces the pulse width and repeats this process until the system times out. When the LOW setting is selected, the pulse width remains at 25% until the target temperature or time is reached (205 minutes for leather and 115 minutes for fabric). The following table provides an overview of the adjustment strategy used to control the amount of current provided to the seat heating elements:
| Parameter name | Definition | Unit | Leather | Fabric |
|---|---|---|---|---|
| Temp_OFF | Maximum temperature for heating program | °C / °F | 67 / 153 | 55 / 131 |
| DH_S3 | PWM for heating - high level 3 | s | 100% | 100% |
| TempSH3 | Maximum temperature for seat heating level 3 | °C / °F | 50 / 122 | 34 / 93 |
| T1S | First timing program for seat heating | min. | 25 | 20 |
| DH_S2 | PWM for heating level 2 | s | 40% | 70% |
| TempSH2 | Maximum temperature for seat heating level 2 | °C / °F | 55 / 131 | 38 / 100 |
| T2S | Second timing program for seat heating | min. | 85 | 35 |
| DH_S1 | PWM for heating level 1 | s | 40% | 34% |
| TempSH1 | Maximum temperature for seat heating level 1 | °C / °F | 60 / 140 | 43 / 109 |
| T3S | Third timing program for seat heating | min. | 145 | 95 |
| DL_S1 | PWM for heating level Low | s | 25% | 25% |
| TempSL1 | Maximum temperature for heating program Low | °C / °F | 65 / 149 | 48 / 118 |
| T4S | Fourth timing program for seat heating | min. | 205 | 115 |
Power supply of the seat heating control unit reaches from relay switch located in the luggage compartment fuse box, through a line protected by a fuse.
Relay switch receives an ignition-operated power supply (INT) from the line protected by a fuse.
The control unit then connects via CAN to the other network nodes.
The BCM receives a direct power supply from the battery through the line protected by a maxi fuse located in the engine compartment junction unit.
The BCM receives an ignition-operated power supply (INT). This signal is used, amongst other things, to "wake up the network".
The coil activation signal reaches the BCM via the LIN line.
| Refer to COMPONENT INDEX . |
The BCM is the communication gateway between the CSWM and the switches.
| Refer to COMPONENT INDEX . |
When a heated seat switch CAN-IHS data bus signal is received by the CSWM from the BCM, the CSWM 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 CSWM sends LED illumination messages to the IPC.
If the CSWM detects a heated seat element OPEN or SHORT circuit, it will record and store the appropriate Diagnostic Trouble Code (DTC).
| Refer to COMPONENT INDEX . |
The vented seat motors will only operate with the engine running and will not operate at the same time as the heated seats. The vented seat motors are controlled by the CSWM. The CSWM provides the vented seat motors with variable analog voltages giving the motors two selectable speeds. These speeds are selected by the driver and/or front passenger by pressing the vented seat switches. Switching the vented seats on while the heated seats are already operating will disable the heating of the seat and start the venting of the seat. Both front vented seats work independently from each other, so that the driver and front passenger can choose there own settings for individual comfort preferences.
| Refer to COMPONENT INDEX . |
with Cushion
- 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 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.
| Refer to COMPONENT INDEX . |
The ICS contains the switch for the heated seat operation. The ICS sends the input command to the BCM.
The IPC sends a LED illumination message to the ICS so that the appropriate LEDs are illuminated for any given heating level.
| Refer to COMPONENT INDEX . |
Uconnect® Touch Screen provides soft buttons to activate and deactivate the heated seat system as well as the vented seat system.
| Refer to COMPONENT INDEX . |
The plenums provide a path for the air to be pulled away from the seat bottom and seat back surfaces for seat ventilation.