HVAC System Failures: 7 Common Causes and How to Prevent Them

If you’re reading this when we publish it, chances are it’s absolutely sweltering outside. And is there anything worse than being on a long haul in this heat with a broken HVAC system? No, of course there isn't!

That’s why we’ve put together this quick guide to seven common causes of HVAC failure and what you can do to prevent them! 

1. Refrigerant Leaks

Cause

Your HVAC system refrigerant absorbs heat from the cabin and releases it outside, allowing for effective cooling. Leaks often occur due to worn seals, corroded components, or damage to the refrigerant lines.

Prevention

• Regularly inspect the hoses and seals for signs of wear and tear.
• Use a leak detection kit to catch small leaks before they become significant issues.
• Ensure proper installation of all components to prevent unnecessary strain and potential leaks.

2. Faulty Compressors

Cause

The compressor is the heart of the HVAC system, responsible for circulating refrigerant through the system. Failure can result from a lack of lubrication, electrical issues, or debris in the system.

Prevention

• Regularly check and replace the compressor's oil to ensure proper lubrication.
• Install a filter drier to remove moisture and debris from the refrigerant.
• Conduct routine inspections to catch electrical issues early.

3. Clogged Air Filters

Cause

Air filters trap dust, pollen, and other particles to keep the air inside your cabin clean. Over time, however, these filters can become clogged, reducing airflow and straining the HVAC system.

Prevention

• Replace air filters according to the manufacturer’s recommendations, typically every 12,000 to 15,000 miles.
• Consider using high-quality filters that capture more particles and last longer.
• Perform visual inspections of the filters regularly, especially if you often drive in dusty conditions.

4. Blower Motor Failures

Cause

The blower motor circulates air through the HVAC system and into the cabin. Electrical issues, worn bearings, or obstructions in the airflow path can cause failures.

Prevention

• Regularly inspect the blower motor and its components for signs of wear.
• Ensure the electrical connections are secure and free from corrosion.
• Keep the airflow path clear of debris to prevent strain on the motor.

5. Thermostat and Sensor Issues

Cause

The thermostat and various sensors regulate the temperature and operation of the HVAC system. Malfunctions can lead to inaccurate temperature readings and improper system operation.

Prevention

• Regularly calibrate the thermostat and check the sensors for accuracy.
• Replace faulty sensors promptly to ensure the system operates correctly.
• Update the system software, if applicable, to ensure compatibility with new sensors.

6. Electrical Problems

Cause

The HVAC system in your truck relies heavily on a network of electrical components, including fuses, relays, and wiring. Electrical issues can disrupt the system's functionality and lead to failures.

Prevention

• Conduct regular inspections of the HVAC electrical system for loose connections, corrosion, and damaged wires.
• Replace blown fuses and faulty relays promptly.
• Ensure the truck’s battery and alternator are functioning correctly to provide consistent power.

7. Evaporator and Condenser Coil Issues

Cause

The evaporator and condenser coils are essential for the heat exchange process in your HVAC system. These coils can become clogged with dirt and debris or develop corrosion, reducing system efficiency and leading to failures.

Prevention

• Regularly clean the evaporator and condenser coils to remove dirt and debris.
• Check for and repair any signs of corrosion or damage.
• Ensure proper airflow around the coils to prevent overheating and maintain efficiency.

Conclusion

Preventing HVAC system failures in your heavy-duty truck is crucial for maintaining a comfortable and safe driving environment. By staying on top of regular maintenance and addressing issues promptly, you can keep your HVAC system running smoothly and efficiently. At E & R Diesel Service, we're here to help resolve any issues you may be suffering from with our professional HVAC repairs.

If you’re looking to stay cool this summer, be sure to check out our essential guide to summer HVAC maintenance!