Test Requirements

• Radiator and condenser are clean (clean if necessary).
• Thermal insulation at expansion valve OK and properly installed. Refer to the appropriate service information. for the vehicle-specific Service Information.
• Ribbed belt is OK and properly tensioned. Ribbed belt for A/C compressor and generator are OK and correctly tensioned. Refer to CYLINDER BLOCK, BELT PULLEY SIDE [CPLA, CPPA, CPKA, CPRA] /CYLINDER BLOCK, BELT PULLEY SIDE [DDSA, DDSB] for the vehicle-specific Service Information.
• All air ducts, covers and seals OK and properly installed.
• Fault finding on the electrical equipment and vacuum system found no malfunction. Refer to the appropriate service information. for the vehicle-specific Service Information.

• The A/C system OBD cannot find malfunctions with the Vehicle Diagnostic Tester in "Guided Fault Finding"  . The measured value block does not show any shut-off condition from the A/C compressor (only on vehicles with "A/C system" OBD).

• Air flow through dust and pollen filter not obstructed by dirt. Refer to COMPONENT LOCATION OVERVIEW - COMPONENTS IN FRONT VEHICLE INTERIOR for the vehicle-specific Service Information.
• The heater and A/C unit does not draw in any secondary air at the highest fresh air blower speed. Evaporator and heater not drawing in secondary air at maximum fresh-air blower speed. Refer to the appropriate service information. for the vehicle-specific Service Information.
• The air flaps in the heater and A/C unit reach their end position. Refer to COMPONENT LOCATION OVERVIEW - COMPONENTS IN FRONT VEHICLE INTERIOR for the vehicle-specific Service Information.
• Fresh-air intake ducts beneath hood and in passenger compartment as well as corresponding water drain valves OK, see vehicle specific Service Information. Refer to COMPONENT LOCATION OVERVIEW - COMPONENTS IN FRONT VEHICLE INTERIOR .
• The engine is warm.
• Vehicle is not exposed to direct sunlight.
• Ambient temperature greater than 15 °C (60 °F).
• All instrument panel vents are open.
• With engine running and maximum cooling output set on air conditioning system:

Refer to the appropriate service information. .

Maximum Cooling Output, Setting

Setting on Front A/C Display Control Head -E87-.

-- Preselect "Auto" mode (A/C compressor on).

-- Set the temperature preset "LO" for the driver and front passenger sides.

Setting on heater controls:

-- A/C button and Rec- or recirculated air button pressed.

-- Temperature dial in the cold position.

-- Fresh-air blower dial in 4 position.

• The Radiator Fan -V7- runs (the fans run) (at least in level 1).

• The Fresh Air Blower -V2- runs at maximum speed
• Recirculation/fresh air door set to "recirculating air mode", back pressure door is closed and air recirculation door opened (within one minute after starting vehicle).
• Is the coolant shut-off valve closed?
• Are the valves on the pump/valve unit closed and the coolant circulation pump is not pumping?