Why does my Kia Sorento Third Generation (2015-2020) AC blow hot air?

Diagnosing Hot Air from the A/C in a 2015-2020 Kia Sorento

Symptoms

• A/C system blows hot air instead of cold.
• A/C compressor not engaging or making unusual noises.
• Visible signs of refrigerant leakage (oil spots or dye).
• A/C control panel lights functioning but no cooling effect.

Diagnostic Steps

1. Visual Inspection

   • Check for any obvious signs of damage or leaks in the A/C system, including the compressor, hoses, and evaporator.
   • Look for refrigerant oil stains, indicating a leak.
   • Inspect the cabin air filter and ensure it is not clogged.

2. Check A/C Controls

   • Ensure that the A/C is set to the correct settings (e.g., temperature, mode).
   • Verify that the A/C switch illuminates when activated.
   • Test the climate control module by cycling through all settings.

3. Verify A/C Compressor Engagement

   • With the engine running and A/C on, observe the A/C compressor.
   • The center hub of the compressor should engage; if it does not, this could indicate a problem with the compressor, electrical system, or refrigerant levels.

4. Refrigerant Level Check

   • Connect a manifold gauge set to the low and high-pressure service ports.
   • A low reading on the low-pressure gauge (below 30 psi) can indicate low refrigerant levels, while a high-pressure reading (above 250 psi) may suggest overcharging or a blockage.

5. Temperature Check

   • Use a digital thermometer to measure the outlet temperature of the A/C vents.
   • If the temperature is significantly higher than the ambient temperature, there may be an issue with the refrigerant or the compressor.

6. Electrical Checks

   • Inspect fuses related to the A/C system in the fuse box.
   • Check for power at the A/C compressor clutch connector using a multimeter.
   • Test the A/C relay by swapping it with a similar relay in the fuse box.

Tools Required

• Manifold gauge set
• Digital thermometer
• Multimeter
• Basic hand tools (screwdrivers, wrenches)
• Flashlight
• Safety goggles and gloves

Repair Instructions

1. If Low on Refrigerant

• Locate Refrigerant Leak: Use a UV dye and black light to find leaks.
• Repair Leaks: Replace faulty components (hoses, seals, or compressor).
• Recharge A/C System: Use a refrigerant recovery machine to evacuate and recharge the system with the correct type and amount of refrigerant.

2. If A/C Compressor Fails

• Replace the A/C Compressor:
  • Disconnect the battery.
  • Remove belts and disconnect electrical connectors.
  • Remove the compressor from its mounting brackets and disconnect the refrigerant lines.
  • Install the new compressor and reconnect all components.
  • Recharge the system.

3. If Electrical Issues are Detected

• Replace Fuses/Relays: If any fuses or relays are faulty, replace them as needed.
• Repair Wiring: Inspect and repair any damaged wiring leading to the A/C compressor or control panel.

4. If Clogged Cabin Air Filter

• Replace Cabin Air Filter:
  • Open the glove box and remove it to access the filter compartment.
  • Remove the old filter and install the new one, ensuring it is properly seated.

5. Test the System

• After completing repairs, reconnect the battery.
• Start the engine and turn on the A/C to verify the system is blowing cold air.
• Monitor the system for any unusual noises or issues.

Conclusion

If you have followed the above steps and the issue persists, it may be necessary to consult a professional technician for further diagnostics and repair. The A/C system is complex, and specialized tools may be required for certain repairs.