Test Requirements

• Ambient temperature greater than 15 °C
• Clean radiator and condenser (clean if necessary).
• The ribbed belt, which drives the A/C compressor, is OK and is tensioned correctly. The ribbed belt is actually driving the A/C compressor.
• All air guides, covers and seal OK and properly installed.
• Air flow through dust and pollen filter not obstructed by dirt.
• Air intake apparatus (in fresh air and recirculating air mode) is not impaired by soiling or components installed as retrofit.
• Vehicle not exposed to sunlight.
• Engine is warm.
• The A/C control module DTC memory was checked and erased and a basic setting was performed using Vehicle Diagnosis, Testing and Information System VAS 5051 under "Guided Fault Finding".

Adjustments on vehicle 

• Open all instrument panel vents.
• Close hood.
• Set the lowest possible temperature (temperature rotary switch turned all the way to cold) on A/C control module.
• Switch on the A/C compressor using the AC  button on A/C control module (indicator lamp in AC  comes on)
• Switch A/C system to recirculating air mode by pressing recirculating air mode button on A/C control module (indicator lamp in recirculating air button lights up).
• Set the air flow direction to instrument panel vents via the air distribution rotary switch on A/C control module.
• Set speed 4 on fresh air blower rotary switch.

Functions with engine running: 

• Fresh Air Blower -V2- runs at maximum speed.
• A/C system initiates recirculating air mode, the fresh air intake is closed and the recirculating air intake is opened (Fresh Air Blower extracts air from passenger compartment under instrument panel / glove compartment).
• The Coolant Fans -V7- run (activation and speed depends on pressure in refrigerant circuit and on the engine temperature).