GF91.30-P-0003CW Heated Seats (HS) Function

GF91.30-P-0003CW Heated Seats (HS) Function
- with CODE (873) Heated left and right front seats

General information
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.

Function requirements
^ C. 15R On
^ SIH operational

The circuit status is transmitted to the rear SAM control unit with fuse and relay module (N10/2) by the electronic ignition lock control unit (N73) via the interior CAN.

The SIH enables the following subfunctions:
^ Manual switching on and off:
^ Automatic switch off

Manual on/off function sequence
Operation takes place via the left front heated seat button
(N72/1s10) and the right front heated seat button (N72/1s11) in the upper control panel control unit (N72/1).

Each actuation of a heated seat button is transmitted to the front SAM control unit with fuse and relay module (N10/1) by the upper control panel control unit via the instrument panel LIN. This transmits the request via the interior CAN to the rear SAM control unit with fuse and relay module (N10/2), which then switches the SIH on.

The following heating elements are actuated by the rear SAM control unit:
^ Left front seat sitting surface heated cushion (R13/1)
^ Left front backrest heated cushion (R13/2)
^ Right front seat sitting surface heated cushion (R13/3)
^ Right front backrest heated cushion (R13/4)

The heat output depends on the number of the times the relevant heated seat button is pressed:
Press once: Heating stage 3 (100 % heat output)
Press two times: Heating stage 2 (70 % heat output)
Press three times: Heating stage 1 (40 % heat output)

Pressing the button again switches the SIH off.

Function indicator
The particular heating stage that is active is indicated via red LEDs in the relevant heated seat button.

Automatic switch off function sequence
The timer control is realized by the rear SAM 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.

The timer settings of the 3 heating stages can be parameterized in the rear SAM control unit using STAR DIAGNOSIS.

Other shutoff criteria:
^ 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, 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.

^ 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 by the rear SAM control unit. Depending on the situation, the HS [SIH] are also deactivated.

^ Switching off in the event of a hardware defect
If heated cushion actuation is detected without a current existing switch-on request or function condition, the SIH is switched off.

^ Shutting off during the engine starting procedure.
The timer control continues to run and the LEDs remain on. No undervoltage is detected during start-up.

^ Switching off in the event of overtemperature.
- Heating stage 3 can no longer be activated if the interior temperature is > 42 °C.
- Heating stage 3 and heating stage 2 can no longer be activated if the interior temperature is > 45 °C.
- The SIH cannot be activated if the interior temperature is > 55 °C.

The current interior temperature value is transmitted to the rear SAM control unit via the interior CAN by the automatic air conditioning control and operating unit (N22/7).

If no plausible interior temperature value is present, the outside temperature value is used instead.