Climate Control Unit Air Flow: Shutters

There are eleven different shutters which direct climate control unit air flow:

• Six temperature shutter for mixing hot and cold air. Three on the lefty and three in the right hand sides. On each side there is one shutter installed (2) upstream and one downstream (3) of the heater element. (1) and (2) together control the amount of air to be heated and (3) guides the hot air to the correct air vent.
• A floor shutter for guiding the air flow to the front and rear.
• A defroster shutter for guiding the air flow to the front windshield and side winders.
  NOTE: Electronic climate control (ECC) has a separate shutter motor for this shutter.
• A ventilation shutter for guiding the air flow to the dashboard and B post.
• A fresh air shutter for guiding outside air flow into the climate control system.
• A recirculation shutter for guiding the air in the passenger compartment flow back into the climate control system.

Timed recirculation 

There is a time limit which is activated by software parameters. Parameters are set in the factory or at after market installation.

If the Air conditioning (A/C) is manually activated (Electronic climate control (ECC), Manual climate control (MCC)):

• Recirculation is switched off after 5 minutes if outside temperature < 7°C (< 44.6°F).
• Recirculation is switched off after 12 minutes if outside temperature is > 7°C (> 44.6°F).

If air conditioning is not activated or if AUTO is activated:

• Recirculation is switched off after 5 minutes if outside temperature < 7°C (< 44.6°F).
• Recirculation is switched off after 12 minutes if outside temperature > 20°C (> 68°F).
• - Recirculation switches off according to a linear function if the outside temperature is between 7°C (44.6°F) and 20°C (68°F).

Speed compensation 

When the vehicle speed is approximately 160 km/h (99 mph) the blower fan switches off. At higher speeds the intake air flow is controlled by the fresh air shutter closing. This reduces the risk of increased airflow into the passenger compartment. At approximately 190 km/h (118 mph) control ceases. The fresh air shutter is then completely closed.

If defroster is elected on the climate control panel speed compensation is deactivated if the vehicle speed exceeds 100 km/h (62 mph). The air is guided to the defroster vents and the fresh air shutter is fully opened. With automatic climate control the Climate control module calculates what position the shutters should be in order to satisfy the requirement.