Front heated seats function - GF91.30-P-0004R

MODEL 230 with CODE (873) Electrically heated left and right front seats 

Fig 1: Front Heated Seats Function Diagram

Courtesy of MERCEDES-BENZ USA

Networking of components 

The seat heater features two heating stages which can be operated together, separately or time-controlled.

In stage 1  the seat heater is clocked with a frequency of f=25 Hz - 30 Hz and 20 % - 33 % active time. In stage 2  the seat heater is switched on permanently.

Time control 

The seat heater is switched over after t= 5 min  . automatically from heating stage "2  " to heating stage "1  ", which operates for t= 30 min. until the seat heater switches off.

The seat heater is operated as follows: 

Driver

• Seat heater stage 1 and 2 switch (S91/2s18)  in the left seat adjustment switch group (S91/2) 

  Front passenger

• Seat heater stage 1 and 2 switch (S92/2s18)  in the right seat adjustment switch group (S92/2);  these are designed as pushbuttons.

Two LEDs in the switch indicate the particular operating state of the heater.

The operation and function of the seat heater are summarized in the table below.

(Driver/passenger) 

The left front seat adjustment with memory control module (N32/1)  and right front seat adjustment with memory control module (N32/2)  control the different electric power consumptions of the seat heaters in the heating stages and the heating period.

If an undervoltage ≤ 11 V  exists the seat heater is switched off automatically  and it cannot be switched on. The LEDs in the seat heater switch flash  . If the undervoltage exists for longer than 30 s  , a fault is then stored in the memory.

The seat heater is switched off if a seat adjustment is performed.

If the seat ventilation is switched on, the seat heater is not switched off until the seat ventilation is switched off.