SEAT WARMER SYSTEM


id091300101200


Outline

•  The seat warmer system is controlled by the seat warmer control unit.

Functions

•  The seat warmer system warms the occupants in the seats by warming the seat cushions and the seat backs.

Structure/Construction


Construction

•  The seat warmer system consists of the following parts:

Front

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Second-row

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System wiring diagram

Front (without seat ventilation system)

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Front (with seat ventilation system)

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Second-row (without seat ventilation system)

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Second-row (with seat ventilation system)

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Operation


Front

Example: Driver's seat warmer unit is operated

1.  When the seat warmer switch (driver) is operated (1), the indicator unit or the front climate control unit sends (2) a temperature level signal according to the seat warmer switch operation to the seat warmer control unit.

2.  When the seat warmer control unit receives a temperature level signal from the indicator unit, it turns the transistor on (3) and the relay on (4).

3.  When the relay turns on, power is supplied (5) to the driver's seat warmer unit and the seat warmer unit warms.

•  If the seat warmer control unit detects that the temperature around the seat warmer unit exceeds the set value by the thermistor, the power supply is cut.
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Second-row

Example: Seat warmer temperature level on left side second-row seat is set at 3:

1.  When the CPU of the second-row seat warmer switch detects the second-row seat warmer switch (LH) operation, it sends (1) a switch operation signal (temperature level “3”) to the CPU of the second-row seat warmer control unit.

2.  When the CPU of the second-row seat warmer control unit receives the switch operation signal (temperature level “3”) from the second-row seat switch, it sends current to the transistor to turn it on (2).

3.  Current flows (3) to the FET by turning the transistor on.

4.  The current flows (4) to the relay coil to turn the relay switch on (5).

5.  When the relay switch is turned on, the ground circuit is established and the current flows (6) to the second-row seat warmer unit in the second-row seat cushion (LH) and second-row seat back (LH).

6.  The heating wire warms up (7) by the current sent to the second-row seat warmer unit in the second-row seat cushion (LH) and second-row seat back (LH).

•  When the CPU of the second-row seat warmer switch detects that the temperature around the seat reaches approx. 44°C {111°F}, the power supply is cut off.
Note
•  The CPU in the second-row seat warmer switch does not store the temperature level of the second-row seat warmer. When the ignition is switched OFF at the temperature level 1 to 3, and the ignition is switched ON again (engine off or on), the temperature level becomes “0”.
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Fail-safe

•  Not applicable