Seat Heating

Seat Heating

Seat heating is an option or part of the cold weather package.







The following components are required for the seat-heating function:

- Switch block, auxiliary functions, driver and passenger
- BZM
- Controller (CON)
- Control display (CD)
- Car Access System (CAS)
- Seat module, driver and passenger (SMFA/SMBF)
- 2 rapid heating elements per seat
- 2 regular heating elements areas per seat
- 4 temperature sensors

The switch block contains the control button and 3 orange LEDs. The LEDs indicate the various heating stages.

The signals for operating the seat heating are transmitted over the buses.

Signal path: Button 14-pin ribbon cable BZM K-CAN S CAS K-CAN P SMFA or SMBF.

The seat modules incorporate activation and control of seat heating. Each seat has 4 heating elements, which are sewn into the seat cover:

- 1 rapid heating element in each inner seat cushion area and in inner backrest area.
- 1 residual heating element in each outer seat cushion area and in outer backrest area.

Each heating element is monitored by an NTC temperature sensor.




Activation of Heating Areas

When the seat heating is turned on, the rapid heating elements are activated first in order to heat up the seats quickly.

Activation of all the heating elements is PWM so that an established current intensity is not exceeded during regular heating. The duty factor is dependent on the selected heating stage, the ON period and the heating-area temperatures.

After the initial rapid heating, the regular heating areas are activated in order to ensure a uniform distribution of temperature in the seat.







The function indicators (LEDs) of the seat heating remain on if the heating is briefly deactivated (e.g. during seat adjustment or by power management).

0peration

The seat heating can be turned on from terminal 15 and the engine running. Stage 3 (maximum temperature) is activated when the button is pressed for the first time. Each subsequent pressing of the button selects the next stage lower or "off". The seat heating is turned off if the button is pressed for longer than 1.2 seconds.

The seat heating remains in stand-by (service station feature) for 15 minutes after terminal 15 is switched off.

Balance Control

The vehicle occupant can use a balance controller to adjust a temperature differential between the seat cushion and the backrest up to +/- 3°C.

The balance controller can be called up in the Control Display and is set with the Controller. This setting remains permanently stored specifically to each Remote Control (Key Memory activated).

For balance control, switch to the Climate menu and call up seat heating from the second page. Select driver's or passenger seat.




The driver's or passenger seat can be selected in this menu. Turn the Controller to vary the balance of heat output between the seat surface and the backrest. This change in balance is indicated by a red/white coloring of the seats in the Control Display.