Seat Heaters System Description
Control/Function
Front Seat Heaters
The front seat heater control unit sets the seat heater to High/Mid/Low or OFF based on the seat heater switch signals received from the climate control unit via B-CAN. The front seat heater control unit monitors the thermistor resistance, the voltage/current/temperature to the heater, and the presence of communication with the climate control unit. Also, the system stores DTCs when a malfunction is detected in the front seat heater control unit.
Rear Seat Heaters
The rear seat heater control unit receives a switch signal and controls the temperature setting (High/Mid/Low) based on the value of thermistor built in the rear seat heater. When a certain period of time has elapsed after the thermistor value reaches the threshold value, the rear seat heater control unit automatically lowers the set temperature to one lower level.
Rear seat heater control unit has a self-diagnostic function related to the thermistor.
Automatic Operation
Based on the outside air temperature, A/C target temperature and other factors, the climate control unit calculates the optimal front seat heater setting. The climate control unit sends this setting request to the front seat heater control unit via B-CAN. When operating in auto mode or during remote engine start, the front seat heater control unit will operate per B-CAN setting request from the climate control unit.
Thermistor and Breaker
The seat cushion heater has a thermistor and breaker. The thermistor and breaker protect the seat heater circuit from overheating. The value of the thermistor is inputted to the control unit.
Front (Type A)
Front (Type B)
Rear (Type A)
Rear (Type B)
The seat heater temperature is controlled by breaker ON and OFF condition.
| ON | OFF | |
|---|---|---|
| Breaker | 95 - 113 deg.F (35 - 45 deg.C) | 115 - 129 deg.F (46 - 54 deg.C) |