Why Does a Car's Air Conditioner Blow Hot Air?
2 Answers
The following are the reasons why the air conditioner blows hot air: 1. Overheating protection of the compressor: If the compressor is overloaded (or even if there is too much refrigerant), causing the compressor temperature to rise too high, it will automatically shut down for protection. 2. Overcurrent protection of the compressor: If the compressor is overloaded (or gets stuck due to a malfunction), or if the generator suddenly provides excessive current, the compressor will shut down due to overcurrent protection. 3. Temperature sensor on the condenser: If the external temperature is too high and the air conditioning load is too heavy, leading to poor heat dissipation and excessive condenser temperature, the signal from the temperature sensor will cause the air conditioning compressor to stop working. 4. Temperature sensor on the evaporator: If it malfunctions, it may send incorrect signals, causing the compressor to stop working.
As a seasoned mechanic with over a decade of experience, I often hear complaints about car ACs blowing hot air, which mainly stems from three common causes. First, insufficient or leaking refrigerant prevents the compressor from cooling properly, resulting in only hot air being blown out. Second, a malfunctioning temperature control switch or blend door, responsible for adjusting the hot/cold air ratio, may get stuck in the hot air position when faulty. Third, driver error, such as forgetting to press the A/C button or setting the temperature too high. I recommend first checking the car settings to confirm cooling mode is on and the temperature is set low. If the issue persists, promptly visit a professional repair shop to inspect the system and recharge the refrigerant, avoiding risks of driver fatigue or heatstroke in hot weather. Regular AC maintenance every six months can prevent these issues.
