HEATED STEERING WHEEL SYSTEM

FUNCTION OF MAIN COMPONENTS

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

   Component		Function
   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	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 surface temperature.
   	Thermistor	Sends a heater wire temperature signal to the steering wheel heater control assembly.
   	Heater Wire	Increases the steering wheel assembly surface temperature using power supplied by the steering wheel heater control assembly.
   	Thermostat	Stops current flow in the heater wire when the steering wheel surface temperature exceeds a threshold.

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 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.

CONSTRUCTION