System Overview

System Overview

MCC (Manual Climate Control) is a system for manually controlling the climate system. The MCC unit consists of a control panel with four knobs; two for temperature, one for air-distribution and one for fan speed. The heated rear window, air recirculation and A/C (if fitted) are operated with buttons.

The following functions can be controlled from the control panel:

Temperature, separately for passengers and driver
The control module supplies power to a stepping motor that turns the air-mixing flap for the driver's zone. Another stepping motor turns the air-mixing flap for the front seat passenger and via a link system the air-mixing flap for the rear seat passengers. The air-mixing flap mixes cold air from the evaporator with warm air from both the evaporator and the heat exchanger. The linkage to the rear seat passengers' air-mixing flap is adjusted so that the temperature at the rear seat corresponds to the temperature for the front seat passenger.

Certain engine variants are equipped with a circulation pump to improve the flow of coolant through the heat exchanger. The pump is supplied with power from the +54 circuit and therefore operates continuously while the engine is running.

Air distribution
The control module supplies power to a stepping motor that turns the air-distribution flap for the driver's zone and front seat passenger and via a link system the air-distribution flap for the rear seat passengers. Consequently, air distribution is the same for the passenger and driver's zones. The air flow can be distributed to defrost, floor/rear door windows or dashboard/center outlets.

Fan speed
The control module regulates a ventilation fan control unit that supplies the ventilation fan motor.

Recirculation
The control module supplies power to a DC motor that turns the recirculation flap. An LED indicates that recirculation is operative.

A/C
The button supplies B+ to DICE if the ventilation fan is running. An LED indicates the B+ is being output. DICE requests engagement of the A/C.

Electrically heated rear window and mirrors
The button switches the heated rear window on and off. When the heating is on, the control module requests the engagement of the rear window heating by outputting a B+ pulse to DICE.

An LED indicates that DICE has operated the heated rear window relay.