What Causes a Car Air Conditioner to Blow Hot Air Instead of Cold?

[MacColin]

There are several main reasons why a car air conditioner blows hot air: 1. Check if the cooling mode is activated: Without turning on the cooling function, no cold air will come out. The cooling switch for a car air conditioner is the AC button. 2. Verify if the external circulation is turned on: Running the air conditioner while the external circulation is on essentially draws hot air from outside into the car, naturally reducing the cooling efficiency. Therefore, during hot weather, it's advisable to switch back to internal circulation after using the external circulation for ventilation. 3. Determine if the car's air conditioning system is low on refrigerant: If the car is two to three years old and the air conditioner is no longer cooling effectively, it's highly likely due to a lack of refrigerant. Refrigerant loss is usually caused by leaks, which can be either due to a malfunction or normal wear. Normally, there might be minor leaks in the air conditioning pipes or condenser, so it's common to need a refrigerant refill every two to three years.