Automotive Heating and Air Conditioning System Troubleshooting

Insufficient Heating System Causes

Insufficient heat is often caused by:

• Poor air circulation or blocked air inlets.
• Heater core obstructions.
• Deterioration of the heating valve.
• Low engine coolant levels.
• A thermostat stuck in the open position.

Excessive Heating System Causes

Excessive heat may be caused by:

• Control cables or hatches that are stuck or misaligned.
• A thermostat stuck in the closed position.

Air Conditioning Verification Process

Start the vehicle and maintain 1500 to 2000 RPM. Run the air conditioning at intermediate speed for 10 minutes. Use a suitable thermometer to measure the ambient temperature and the interior vehicle temperature.

Pressure Gauge Readings

Pressure readings can vary based on the controller and weather conditions.

Low and High Pressure Anomalies

Anomalies with low and high values may indicate:

• Hot water filtration into the heater due to improper tap shutdown.
• Humidity in the installation; dry the system and replace the filter.
• Reversed tubes at the compressor.
• Compressor damage or a seized valve.

Air Conditioning Leak Detection

Leak detection can be performed using fluorescent dyes, which are also compatible with engine oil, transmission fluid, and fuel systems.

Work Method

1. Load the dye into the low-pressure injector.
2. Start the engine and run the air conditioning for a short time to circulate the dye.
3. With the engine running, use an ultraviolet lamp and protective goggles to detect the leak.
4. Apply a sticker indicating the system contains fluorescent dye.

Compressor Maintenance

If damage is found, repair or replace the unit. Before each refrigerant recharge or after repairs, verify the compressor oil level and periodically check the tightness of the compressor mounting screws.

Condenser Maintenance

The condenser contains refrigerant in liquid and gas states under high pressure. Exercise extreme caution during inspection. Due to the nature of the component, it is often necessary to replace the condenser rather than attempt repairs when it fails.