HEATED STEERING WHEEL SYSTEM
The heated steering wheel system heats the steering wheel assembly when the steering heater switch is operated.
The heated steering wheel system uses a thermistor inside of the steering wheel assembly to detect the heater temperature and maintain the set temperature.
The heated steering wheel timer function turns off the heater after a predetermined period of time.
HEATER CONTROLLER SYSTEM
Operation description
When the engine switch is on (IG), pressing the steering heater switch illuminates the LED and current is output from the steering wheel heater control assembly to the steering wheel heater unit of the heated steering wheel system. Pressing the steering heater switch again turns off the LED and stops the current from being output.
A thermostat is installed in the steering wheel heater unit as a safety mechanism.
The steering heater switch LED will blink at 0.3 second intervals when either of the following occurs: 1) an open or short in the steering wheel heater unit thermistor continues for 2 seconds or more; or 2) the steering heater switch is pressed continuously for 10 seconds or more.
If the normal condition is restored for 2 seconds or more, the previous operation before the malfunction occurred continues. However, regardless of if a malfunction is detected and the malfunction operation is occurring, and regardless of if the normal condition is restored and the system is operating normally, the timer will turn off the heater 30 minutes after the steering heater switch was first turned on.
Signal input / output description
| Signal | Signal Name | Function | Signal Type |
|---|---|---|---|
| Input | Thermistor input | Input of voltage corresponding to heater temperature | Analog input |
| Input | Temperature setting input | Input of voltage corresponding to temperature setting | Analog input |
| Input | Operating switch input | Input of power circuit latch operation estimate signal | LOW / HI input |
| Output | LED output | Output of LED | LOW / HI input |
| Output | Heater output | Output of heater | LOW / HI input |
| Output | Latch output | Power circuit maintenance | LOW / HI input |
Safety function
| Content | Operation |
|---|---|
| When thermistor malfunction is detected | Heater off |
| When overheating (175°C (347°F)) of controller is detected | Heater off |
| When load short current (50 A or more) is detected | Heater off |
| When undervoltage (4.5 V) is detected | Heater off |
| OFF timer (30 min.) | After preset time of timer passes, heater off |
| Reverse voltage protection | Protection circuit operates |