HEATED STEERING WHEEL SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


    1. The main components of the heated steering wheel system are as follows:

      Component Function
      Refreshing Seat Switch Steering Heater Switch Used to switch the heated steering wheel system on and off.
      Steering Heater Switch Indicator Light Illuminates when the heated steering wheel system is on. When a malfunction is detected it does not illuminate in order to warn the driver.
      Steering Wheel Assembly Steering Wheel Heater Control Assembly*1 Calculates an appropriate amount of electric current for the heater wire and controls the current to the heater wire to obtain an appropriate steering wheel assembly surface temperature.
      Steering Vibration and Heater ECU*2
      Thermistor

      • Sends a heater wire temperature signal to the steering wheel heater control assembly.*1

      • Sends a heater wire temperature signal to the steering vibration and heater ECU.*2
      Heater Wire

      • Increases the steering wheel assembly surface temperature using power supplied by the steering wheel heater control assembly.*1

      • Increases the steering wheel assembly surface temperature using power supplied by the steering vibration and heater ECU.*2
      Thermostat Stops current flow in the heater wire when the temperature exceeds a threshold.

      *1: Models without lane departure alert system

      *2: Models with lane departure alert system

  2. SYSTEM CONTROL


    1. The heated steering wheel system has the following controls:

      Control Outline
      Basic Control

      • The steering wheel heater control assembly receives the heater wire temperature signal from the thermistor. Based on this signal, the amount of electric current to be sent to the heater wire is calculated to keep the steering wheel surface temperature at approximately 37°C (98.6°F).*1

      • The steering vibration and heater ECU receives the heater wire temperature signal from the thermistor. Based on this signal, the amount of electric current to be sent to the heater wire is calculated to keep the steering wheel surface temperature at approximately 37°C (98.6°F).*2
      Overheat Protection Control The thermostat stops the current flow in the heater wire circuit when the temperature of the heater wire reaches approximately 55°C (131°F) in order to stop heating. Heating will resume when the heater wire temperature decreases to approximately 40°C (104 °F).
      Timer Control Shuts off the heated steering wheel system when 30 minutes elapse after the system is turned on using the steering heater switch.

      *1: Models without lane departure alert system

      *2: Models with lane departure alert system

  3. FAIL-SAFE


    1. If the steering wheel heater control assembly detects a malfunction in the heater steering wheel system, the steering heater switch indicator light does not illuminate. For details, refer to the Repair Manual.*

      *: Models without lane departure alert system

    2. If the steering vibration and heater ECU detects a malfunction in the heater steering wheel system, the steering heater switch indicator light does not illuminate. For details, refer to the Repair Manual.*

      *: Models with lane departure alert system