Seat Heating Control: Components

The buttons for the seat heating are integrated in the switch block of the center console. They have a 3 stage design. At the first switch stage, the seat heating is switched on at maximum power.

After pressing the button for the second time, the moderate power level is switched on.

In the third switch stage, the seat heating is switched on at the lowest power.

Pressing the button again switches the seat heating off. Additionally, the seat heating can be switched off from any setting by pressing the button for at least 1.2 s.

The center console switch block is connected to the air conditioning control unit (IHKA/IHKR) via a ribbon cable. The A/C control unit establishes the connection to the K-CAN.

The junction box has one control outlet for the driver's seat heating and one for the front passenger's seat heating. The signal from the junction box is pulse width-modulated. The frequency of the signal is 25 Hz.

The seat heating modules contain the evaluation of the signals from the junction box. Each seat heating module has three connectors. One connector establishes the connection to the vehicle. The other two connectors are for connecting the seat heating in the seat surface and the seat backrest.

The seat heating consists of one heating mat in the seat backrest and one in the seat surface. The heating mats form a single circuit system. There is an NTC resistor in the seat surface heating mat for regulating the seat heating temperature. The seat heating can be activated from terminal 15