GF91.30-P-0002FL Electric Seat Ventilation, Function

GF91.30-P-0002FL Electric Seat Ventilation, Function

Function requirements, general
^ Circuit 15R On

The electronic ignition lock control unit (N73) transmits the circuit status of circuit 15 to the interior CAN (CAN B).

Seat ventilation, general
The seat cushions and backrests of the front seats can be ventilated in three stages using the seat ventilation.

During comfort opening of the vehicle, the seat ventilation of the driver seat is switched on in stage 3. If circuit 15R is not switched on at this time, the seat ventilation is switched off after t = 5 min.

More detailed information can be found in the function description for the convenience feature (CF [KFB]).

The electric seat ventilation function comprises the following subfunctions:
^ Function sequence, switching on, over and off manually
^ Automatic switch off function sequence

Function sequence, switching on, over and off manually
The seat ventilation is switched on and off with the left seat ventilation button (N72/1s13) and right front seat ventilation button (N72/1s14) in the upper control panel control unit (N72/1) and the ventilation output is regulated.

Each actuation of the relevant seat ventilation button is transmitted by the upper control panel control unit to the front SAM control unit with fuse and relay module (N10/1) via the instrument panel LIN (LIN 1). It transmits the request to the rear SAM control unit with fuse and relay module (N10/2) via the interior CAN. The rea SAM control unit then actuates the left front seat ventilation blower regulator (N29/5) or right front seat ventilation blower regulator (N29/6).

The following motor groups are actuated by the left front seat ventilation blower regulator:
- Left front seat cushion seat ventilation motors (M18/9)
- Right front seat cushion seat ventilation motors (M18/10)

The following motor groups are actuated by the right front seat ventilation blower regulator:
- Right front seat cushion seat ventilation motors M18/11
- Right front backrest seat ventilation motors M18/12

The seat ventilation depends on the ventilation stage selected by means of each seat ventilation button. The function indication for each activated ventilation stage is effected through three blue LEDs in each seat ventilation button.

Press once: Stage 3 of seat ventilation, 3 LEDs
Press two times: Stage 2 of seat ventilation, 2 LEDs
Press three times: Stage 1 of seat ventilation, 1 LED
Press four times: Seat ventilation switched off, no LED

Automatic switch off function sequence
- Shutting off after circuit 15R Off.
If circuit 15C remains On, the timer control continues to run for t = 5 min. If circuit 15R is switched on again, the seat ventilation is also switched on in the previously activated ventilation stage.

- Shutting off in the event of undervoltage or overvoltage.
If the rear SAM control unit switches off the seat ventilation motors, the LED for each seat heater button initially stays on. If the on-board electrical system reaches its normal voltage within the next t = 3 min., the seat ventilation function is automatically reactivated.

However, if the shutoff lasts longer than t = 3 min., the LED in the seat ventilation button is also switched off.

It the shutoff procedure continues and the function is requested again for the corresponding seat ventilation button, the LED comes on for t = 1.5 s and then goes out.

- Switching off by on-board electrical system management system.
In order to prevent the battery from discharging in all driving cycle phases, the state of charge is continuously evaluated. Depending on the situation, the seat ventilation is also deactivated if necessary.

- Shutting off during the engine starting procedure.
During a start sequence, only the seat ventilation motors are switched off. The LEDs in the function indicator are still illuminated. Undervoltage is not recognized while starting and no faults are stored.
- with CODE (401) Front comfort seats, including seat heating and seat ventilation