Front Heated Seats Function - GF91.30-P-0004GW

Model 463 (except 463.342) 

as of model year 2013 up to model year 2019 

Model 463.342 

with code H10 (Seat heaters for driver and front passenger) 

Courtesy of MERCEDES-BENZ USA

Function requirements, general 

• Circuit 15R ON

The electronic ignition lock control unit sends the circuit 15 status over the interior CAN to the SAM control unit.

Seat heater (SIH), general 

The seat heater enables the seat cushions and backrests of the front seats to be heated in three heating levels.

The seat heater function includes the following subfunctions:

• Switch seat heater on and off manually 
• Switch seat heater off automatically 

Switch seat heater on and off manually 

The seat heater is operated using the left front seat heater button or the right front seat heater button in the upper control panel control unit.

Except code E11 (Stealth lights with convoy marking): 

The upper control panel control unit directly reads in the requirements via the seat heater buttons and sends these via the battery sensor LIN SAM control unit and interior CAN to the driver seat control unit or the front passenger seat control unit.

With code E11 (Stealth lights with convoy marking): 

The upper control panel control unit directly reads in the requirements via the seat heater buttons and sends these via the stealth lights LIN, stealth lights control unit, battery sensor LIN, SAM control unit and interior CAN to the driver seat control unit or front passenger seat control unit.

The driver seat control unit actuates the following components:

• Left front seat sitting surface heated cushion
• Left front backrest heated cushion

The front passenger seat control unit actuates the following components:

• Right front seat sitting surface heated cushion
• Right front backrest heated cushion

The heat output depends on the selected heating level. The heating level that is active is indicated via red LEDs in the relevant seat heater button.

Except code E11 (Stealth lights with convoy marking): 

The driver seat control unit or front passenger seat control unit sends the status of the seat heater via the interior CAN, SAM control unit and battery sensor LIN to the upper control panel control unit.

With code E11 (Stealth lights with convoy marking): 

The driver seat control unit or front passenger seat control unit sends the status of the seat heater via the interior CAN, SAM control unit, battery sensor LIN, stealth lights control unit and stealth lights LIN to the upper control panel control unit.

The upper control panel control unit directly actuates the LEDs in the seat heater buttons.

• Operate one time: Heating level 3, heat output 100 % (three LEDs illuminate)
• Operate twice: Heating level 2, heat output 65 % (two LEDs illuminate)
• Operate three times: Heating level 1, heat output 35 % (one LED illuminates)
• Operate four times: Seat heater is switched off (no LED illuminates)

If the seat heater is selected again with the same circuit status, the driver seat control unit or front passenger seat control unit actuates the seat heater at heating level 3 with 90 % heat output.

Model 463 (except 463.342)

as of model year 2013 up to model year 2019

with code S50 (Seat ventilation for driver and co-driver seats)

In automatic mode, heating level 1 of the seat heater is only switched off together with the seat ventilation if the seat ventilation is activated.

Switch seat heater off automatically 

Then the seat heater is automatically switched off (timed). The timer control is implemented via the driver seat control unit or the front passenger seat control unit.

• Heating level 3 is activated for 8 min. Then the system automatically switches to heating stage 2.
• Heating stage 2 is activated for 10 min. Then the system automatically switches to heating level 1.
• Heating level 1 is activated for 35 minutes. Then the seat heater is automatically switched off.

The respective duration of the heating levels can be adjusted using the diagnostic tester in the driver seat control unit or in the front passenger seat control unit.

Shutoff criteria: 

• Shutoff after circuit 15R OFF:

  If circuit 15C remains switched on, the timer control runs on for 5 min. If circuit 15R is switched on again within these 5 min., the seat heater is also switched on at the heating level that has been activated in accordance with the timer control.

• Deactivation with undervoltage or overvoltage:

  The seat heater is switched off in the event of undervoltage or overvoltage. The LEDs initially remain switched on. If normal voltage levels are restored within 3 min., the seat heater starts again automatically. If the shutoff takes longer than 3 minutes, the LEDs are also switched off. If the shutoff continues and the seat heater function is requested again, the LEDs illuminate for 1.5 s and then go off.

• Shutoff for overtemperature of the printed circuit board in the control unit:

• At a printed circuit board temperature of more than 90 °C, heating level 3 can no longer be activated.
• At a printed circuit board temperature of more than 100 °C, heating level 3 and heating level 2 can no longer be activated.
• At a printed circuit board temperature of over 110 °C, the seat heater can no longer be activated.

When a printed circuit board temperature of more than 110 °C is reached, a fault message is stored in the fault memory. Manually switching back on requires cooling at 2 °C below the corresponding temperature threshold.

The interior temperature is used as an alternative for an implausible printed circuit board temperature.

• Shutoff in the event of a hardware defect:

  If the system detects that the heater pads are actuated without a currently existing switch-on request, the seat heater is switched off.

• Shutoff during engine starting procedure:

The seat heater is temporarily switched off during engine start. The timer control continues to run on, however, and the LEDs remain switched on. The starting procedure is not defined as undervoltage.

	Electrical function schematic, seat heater, front		PE91.30-P-2056-97ZGA
	Overview of system components of comfort heating systems	Model 463 (except 463.342) as of model year 2013 up to model year 2019 Model 463.342 as of model year 2017 with code H10 (Seat heaters for driver and front passenger)	GF91.30-P-9990GW