WARNING: The air conditioning system is filled with refrigerant R134a. Observe "Health and Safety Precautions". For further information REFER to: Air Conditioning (A/C) System Recovery, Evacuation and Charging (412-00 Climate Control System - General Information, General Procedures).
Refrigerant circuit check
WARNING: Under certain circumstances, refrigerant lines and A/C components may be extremely hot or cold. Exercising care, touch the refrigerant lines or A/C components in order to check this. Failure to follow these instructions may result in personal injury.
When the A/C system is operating, the following conditions should apply:
Depending on the weather, the refrigerant line may also have ice on its surface
Evaporator outlet line temperature test
To test the power of the A/C system, the temperature at the evaporator outlet line must be measured. To do this, the following preconditions must be met:
NOTE: The temperature measurement cannot be done with a thermometer which makes no contact.
The surface reflection from the metal line may cause incorrect readings.
Connect the temperature sensor (Fluke 80 PK-8) to the outlet line of the evaporator. Locate the temperature sensor as close as possible to the evaporator. Connect the temperature sensor to the multimeter.
Start the engine and allow it to run at idle speed for several minutes.
Switch on the A/C.
After three minutes, measure the surface temperature of the evaporator outlet line.
If the temperature measured is 4 C or lower, the A/C system is OK. If the temperature is higher, the A/C system may be under-filled. For further information, refer to REFER to: Air Conditioning (A/C) System Recovery, Evacuation and Charging (412-00 Climate Control System - General Information, General Procedures).
Frequent faults and their causes
If the cooling power of the A/C system is not adequate, make certain that the temperature control flap(s) is/are operating correctly.
No or poor cooling performance:
Sudden drop in cooling performance (after the air conditioning has been switched off for approx. 5 minutes, the cooling performance returns to normal):
In order to ensure that moisture is completely removed from the refrigerant circuit, the dehydrator should be renewed and the evacuation time should be extended to 2-3 hours. For further information
REFER to: Air Conditioning (A/C) System Recovery, Evacuation and Charging (412-00 Climate Control System - General Information, General Procedures).