Electric seat ventilation, function - GF91.30-P-0002CA

MODEL 207.3/4 with CODE 401 (Front deluxe seats, incl. seat heating and seat ventilation)

Fig 1: Electric Seat Ventilation Block Diagram

Courtesy of MERCEDES-BENZ USA

Function requirements, general

Circuit 15R ON

The electronic ignition lock control unit transmits the status of circuit 15 via the interior CAN to the front SAM control unit and the rear SAM control unit.

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. Detailed information about the comfort opening function can be found in the function description "Theft protection and locking function description" in the subfunction "Convenience feature (CF [KFB]), function".

Seat ventilation function sequence

The operation of the seat ventilation occurs via the front seat ventilation buttons in the upper control panel control unit. When the front seat ventilation button is pressed, the seat ventilation is switched on and off and the ventilation stage is selected. The upper control panel control unit reads in the status of the respective front seat ventilation button directly and sends this to the front SAM control unit via the instrument panel LIN and the rear SAM control unit via interior CAN. The rear SAM control unit actuates the corresponding front seat ventilation blower regulator directly.

The left front seat ventilation blower regulator actuates the following motor groups:

Left front seat cushion seat ventilation motors
Left front backrest seat ventilation motors

The right front seat ventilation blower regulator actuates the following motor groups:

Right front seat cushion seat ventilation motors
Right front backrest seat ventilation motors

The strength of the seat ventilation depends on the selected ventilation stage. The respective active ventilation stage is shown by three blue LEDs in the respective seat ventilation button.

Press once: stage 3 of seat ventilation, 3 LEDs light up

Press twice: stage 2 of seat ventilation, 2 LEDs light up

Press three times: stage 1 of seat ventilation, 1 LED lights up

Press four times: seat ventilation is switched off, no LEDs light up

The rear SAM control unit sends the status of the seat ventilation via interior CAN, front SAM control unit and instrument panel LIN to the upper control panel control unit. The upper control panel control unit actuates the LED in the respective front seat ventilation button directly.

The seat ventilation is switched off under the following conditions:

Shutoff after circuit 15R OFF:
Circuit 15R OFF and circuit 15C ON, the timer control runs on for another t = 5 min. If the circuit 15R is switched on again, the seat ventilation is also switched on again in the previously activated ventilation stage.
Deactivation with undervoltage or overvoltage:
In the event of undervoltage or overvoltage, the rear SAM control unit switches off the seat ventilation. The LEDs in the respective front seat ventilation button initially remain switched on. If the on-board electrical system voltage is stabilized again within t = 3 min, the seat ventilation starts again automatically. If the shutoff lasts longer than t = 3 min, however, the LEDs in the respective front seat ventilation button are also switched off. If the seat ventilation is requested again despite the shutoff, the LEDs light up for t = 1.5 s and then go out again.
Shutoff during engine start:
During engine start, the rear SAM control unit switches the seat ventilation off. The LEDs in the respective front seat ventilation button remain switched on. During the engine start, no undervoltage is recognized and no faults are stored.

	Seat ventilation electrical function schematic		PE91.30-P-2053-97EAA
	Overview of system components of comfort heating systems		GF91.30-P-9990CAM