The heating and air conditioning is controlled by three rotary switches on vehicles equipped with manual temperature control. Movement of the air distribution flaps is carried out by the air distribution flap/temperature flap control unit, which is connected to the control assembly via a rod. Movement of the temperature flap is also carried out by the air distribution flap/temperature flap control unit, which is connected to the control assembly via a cable.
In addition, on the control assembly there is an operating switch for the recirculated air mode and an on/off switch for the air conditioning system.
Climate control assembly - vehicles equipped with automatic temperature control, built up to 03/2007
On vehicles with a DVD navigation system with touchscreen, the control buttons of the automatic temperature control of the heating/air conditioning system are built into this unit. In addition, all heating and air conditioning functions can be controlled via the touchscreen.
Climate control assembly - vehicles equipped with DVD navigation system with touchscreen, built from 01/2008
On vehicles with electronic automatic temperature control (EATC) built from 10/2005, a blower motor with brushes is used.
For this reason, a regulated blower motor resistor is installed in these vehicles instead of the conventional blower motor resistor. This is located in the usual position next to the blower motor, so that the cooling fins of the resistor are cooled by the air flow.
The climate control module regulates the blower motor resistor via a PWM signal, which in turn regulates the voltage at the blower motor to between 3 V and 12.8 V in an infinitely variable manner.
The blower motor resistor is equipped with a temperature monitor, which continuously monitors the internal temperature of the resistor. If the temperature rises above 105°C, the blower motor is switched off until the temperature in the resistor falls to below 100°C.
If the current increases and exceeds a value of 26 A ± 3 A defined in the blower motor resistor (e.g. high dynamic pressure in the blower housing during fast motorway driving), the current flow through the blower motor is limited by the blower motor resistor until a safe value is achieved. If this value cannot be achieved (e.g. blower motor blocked or partially seized or dynamic pressure in the blower housing permanently too high), the value is limited to 6 A ± 2 A.
Under normal conditions, the blower motor control returns to the normal state.
