Function Of Rear Heated Seats - GF91.30-P-0005GW
Model 463.23/24/27, 463.34 (except 463.342)
as of model year 2013 up to model year 2019
Function requirements, general
- Circuit 15R ON
The electronic ignition lock control unit sends the circuit 15 status over the interior CAN to the rear control unit.
Seat heater (SIH), general
The seat heater enables the seat cushions and seat backrests to be heated in three heating levels.
The seat heater function includes the following subfunctions:
- Switch seat heater on and off manually
- Switch seat heater off automatically
Switch seat heater on and off manually
The seat heater is operated using the left rear seat heater button or the right rear seat heater button.
The rear control unit directly reads in the requests via the rear seat heater buttons and actuates the following components accordingly:
- Left rear seat sitting surface heated cushion
- Left rear backrest heated cushion
- Right rear seat sitting surface heated cushion
- Right rear backrest heater pad
The heat output depends on the heating level that has been selected using the respective rear seat heater button. The active heating level is indicated by means of three red LEDs in the respective rear seat heater button. The rear control unit actuates the LED.
- Operate one time: Heating level 3, heat output 100 % (3 LEDs illuminate)
- Operate two times: Heating level 2, heat output 65 % (2 LEDs illuminate)
- Operate three times: Heating level 1, heat output 35 % (1 LED illuminates)
- Operate four times: Seat heater switched off (no LED illuminates)
If the seat heater is selected again with the same circuit status, the rear control unit actuates the seat heater at heating level 3 with 90 % heat output.
Switch seat heater off automatically
Then the seat heater is automatically switched off (timed). The timer control is realized by the rear control unit.
- Heating level 3 is activated for 8 min. Then the system automatically switches to heating stage 2.
- Heating stage 2 is activated for 10 min. Then the system automatically switches to heating level 1.
- Heating level 1 is activated for 35 minutes. Then the seat heater is automatically switched off.
Timer control of the three heating levels is adjusted by means of SCN coding in the rear control unit.
Shutoff criteria:
- Shutoff after circuit 15R OFF:
If circuit 15C remains switched on, the timer control funs on for another 5 minutes. If circuit 15R is switched on again within these 5 min., the seat heater is also switched on at the heating level that has been activated in accordance with the timer control.
- Deactivation with undervoltage or overvoltage:
The seat heater is switched off in the event of undervoltage or overvoltage. The LEDs initially remain switched on. If normal voltage levels are restored within 3 min., the seat heater starts again automatically. If the shutoff takes longer than 3 minutes, the LEDs are also switched off. If the shutoff continues and the seat heater function is requested again, the LEDs illuminate for 1.5 s and then go off.
- Shutoff for overtemperature of the printed circuit board in the control unit:
- At a printed circuit board temperature of more than 90 °C, heating level 3 can no longer be activated.
- At a printed circuit board temperature of more than 100 °C, heating level 3 and heating level 2 can no longer be activated.
- At a printed circuit board temperature of over 110 °C, the seat heater can no longer be activated.
When a printed circuit board temperature of more than 110 °C is reached, a fault message is stored in the fault memory. Manually switching back on requires cooling at 2 °C below the corresponding temperature threshold.
The interior temperature is used as an alternative for an implausible printed circuit board temperature.
- Shutoff in the event of a hardware defect:
If the system detects that the heater pads are actuated without a currently existing switch-on request, the seat heater is switched off.
- Shutoff during engine starting procedure:
The seat heater is temporarily switched off during engine start. The timer control continues to run on, however, and the LEDs remain switched on. The starting procedure is not defined as undervoltage.
| Electrical function schematic, seat heater, rear seats | PE91.30-P-2055-97ZGA | ||
| Overview of system components of comfort heating systems | GF91.30-P-9990GW |