Heated seats (HS) function - GF91.30-P-0003SC

MODEL 216.3 up to Model Year 8 

Function requirements: 

• Circuit 15R On

Function 

Using the heated seats (HS [SIH]), it is possible to heat the seat cushions and the backrests of the front seats in three heating stages.

Operation takes place via the heated seat switches that are designed as buttons.

Each actuation is transmitted via front door LIN to the respective door control unit, which transmits the signal via the interior CAN to the corresponding seat control unit:

Press once: Heating stage 3 (100 % heat output)

Press two times: Heating stage 2 (60 % heat output)

Press three times: Heating stage 1 (30 % heat output)

When the button is pressed again, the heated seats are deactivated.

Function indicator 

The particular heating stage that is active is indicated via red LEDs in the corresponding heated seat switch.

Operating front passenger heated seat from driver seat 

The driver can use the seat adjustment selection switch to operate the HS [SIH] of the front passenger seat. The switchover remains active for approx. 10 s.

Timer control (automatic shutoff) 

The timer is controlled by the particular seat control unit:

• Heating stage 3 is active for 5 min.

  Then the system automatically switches to heating stage 2.

• Heating stage 2 is active for 10 min.

  Then the system automatically switches to heating stage 1.

• Heating stage 1 is active for 20 min.

Then the HS [SIH] are automatically switched off.

Additional shutoff criteria 

• Shutting off after circuit 15R Off.

  If circuit 15C remains On, timer control continues to run for 5 min. If circuit 15R is switched on again, then the HS [SIH] are also switched on at the heating stage active according to the timer control.

• Shutting off in the event of undervoltage or overvoltage.

  The timer control continues to run. The LEDs of the function indicator come on briefly in the event of undervoltage and then go out.

• Shutting off through vehicle power supply control unit (N82/1).

  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 HS [SIH] are also deactivated.

• Shutting off during a seat adjustment.

  The timer control continues to run during the seat adjustment, the LEDs remain on.

• Shutting off during the engine starting procedure.

  The timer control continues to run and the LEDs remain on. During the starting procedure, undervoltage is not detected and no flashing due to undervoltage is activated.

• Shutting off with code (889) Keyless Go

As faults may occur during the inductive search for the transmitter key (A8/1) in the interior compartment, the HS [SIH] are switched off during this period.

Heated seats (SIH) location of components		GF91.30-P-0003-02SC
Heated seats (HS) block diagram		GF91.30-P-0003-03SC
Left front seat control unit, component description	N32/1	GF91.29-P-5230SX
Right front seat control unit, component description	N32/2	GF91.29-P-5240SX
Driver-side front door control unit, component description	N69/1	GF72.29-P-6000SC
Passenger-side front door control unit, component description	N69/2	GF72.29-P-6010SC
Electronic ignition/starter switch control unit (EIS) component description	N73	GF80.57-P-6000SX
Front seat adjustment switch group, component description	S22, S23	GF91.29-P-5220SX