In this article, we will quickly explore the three most common failures in automotive air conditioning systems and the recommended actions to resolve them.
First Failure: Normal Airflow but No Cold Air
When the air conditioning is turned on, there is airflow, but it is not cold. This issue can have several causes. Before taking action, remember that the normal temperature of the air at the vent outlets should range between 0 and 10 °C.
A. Gradual Failure
- Likely caused by small refrigerant leaks.
- Solution: Visually inspect the system hoses, paying special attention to the joints. Oil stains are indicative of leaks.
B. Compressor Issues
- For conventional compressors, if the activation clutch works correctly, examine the compressor pipes.
- Under normal operation:
- The thicker pipe should be cold, approximately 10 °C.
- The thinner pipe should be around 70 °C.
- If these temperatures are not reached, a gas leak is likely.
C. Pressure Readings
- Using pressure gauges, check the system pressures:
- Blue gauge: approximately 35 PSI.
- Red gauge: approximately 180 PSI.
- Perform these measurements with the air conditioning on and without accelerating the engine.
D. Sudden Failure in Compressors with Clutches
- If you don’t hear the pulley engagement noise when turning on the air conditioning:
- Check: fuses, relays, and the system pressure switch. A faulty pressure switch may prevent power from reaching the compressor clutch.
E. Voltage and Continuity Verification
- Check if the compressor coil receives voltage when the air conditioning is turned on.
- Test the coil’s electrical continuity using a digital multimeter in resistance mode.
Second Failure: Minimal Airflow but Cold Air
This failure occurs when the system produces cold air but with very low airflow.
A. Dirty Air Filter
- Inspect and replace the air filter according to the car model.
B. Obstructed Ducts
- This may be caused by an internal blockage due to a faulty air control window servo motor.
C. Turbine Fan Issues
- Ensure the turbine fan is functioning properly.
- If you cannot access the fan, listen for unusual noises and check the motor’s electrical consumption by tracing the electrical lines.
Third Failure: Bad Odor When Turning on the Air Conditioning
A bad odor may result from a dirty cabin pollen filter.
A. Filter Replacement
- Replace the cabin pollen filter as needed.
- If the odor persists, clean the ducts with antibacterial spray or foam.
B. Proper Use of Antibacterial Products
- Follow the manufacturer’s instructions when applying these products.
- Protect the vehicle’s upholstery and wear a mask during the process.
C. Clogged Condensation Drainage Tube
- Ensure the drainage tube is not blocked to prevent the accumulation of fungi and bacteria that cause bad odors.
