HEATED STEERING WHEEL SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Component Function
    Steering Wheel Assembly Steering Wheel Heater Control Assembly 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.
    Heater Wire Increases the steering wheel assembly surface temperature using power supplied by the steering wheel heater control assembly.
    Thermistor Sends a heater wire temperature signal to the steering wheel heater control assembly.
    Thermostat Stops current flow in the heater wire when the temperature exceeds a threshold.
    Steering Pad Switch Assembly Steering Heater Switch Used to switch the heated steering wheel system on and off.
    Combination Meter Assembly Steering Heater 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.

  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).
      Overheat Protection Control The thermostat stops the current flow in the heater wire circuit when the heater wire temperature 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.

  3. FAIL-SAFE


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