What Causes No Cooling or Airflow in Car AC at High Speeds?
4 Answers
The reasons why a car's air conditioning does not cool or blow air at high speeds are as follows: Reason 1: Too much dirt and dust on the condenser, leading to poor cooling performance. Reason 2: Too much debris in the air filter, affecting the blower's air intake and reducing airflow. Reason 3: Excessive dirt on the evaporator, significantly impacting both air intake and cooling, thereby severely affecting the AC's cooling performance. Reason 4: Ice formation on the evaporator surface, severely obstructing the AC's airflow. Below is an introduction to car air conditioning: Introduction 1: The heating principle of car air conditioning is simple. When the heating function is turned on, high-temperature coolant from the engine flows through the heater core, and the air blown by the blower passes through the heater core, allowing warm air to be blown out from the AC vents. Introduction 2: The cooling principle of car air conditioning is also straightforward. When the AC button is pressed, the AC compressor clutch engages, allowing the engine to drive the compressor. The compressor continuously compresses the refrigerant and sends it to the evaporator. Introduction 3: When the refrigerant expands in the evaporator, it absorbs heat, cooling the evaporator. The cooled evaporator then cools the air blown by the blower, allowing cold air to be blown out from the AC vents.
I also encountered a situation where the air conditioning wasn’t cooling and there was no airflow while driving on the highway the other day—it was quite frustrating. At high speeds, the engine is under heavy load, which can lead to refrigerant leaks or pipe ruptures, causing the system to fail. The fan not spinning could also be due to a blown fuse or relay from excessive vibration at high speeds, a faulty fan motor, or a loose belt preventing it from turning. A malfunctioning temperature sensor might mislead the system into shutting off the cooling. It’s best to pull over safely first and check if the fan isn’t spinning, then try replacing the fuse. If that doesn’t work, get it repaired as soon as possible—the heat on the highway can easily lead to heatstroke, making it very unsafe. Regular maintenance of the air conditioning system can prevent such issues, so never ignore minor problems.
This situation is really frustrating. I suspect it's most likely a faulty air conditioning switch or an electrical issue. When driving at high speeds, the fan might have burned out or become blocked, preventing air from coming out; as for cooling, a broken compressor clutch or insufficient refrigerant can cause the air conditioning to fail. It could also be that the air baffle is stuck, blocking the air duct. After stopping, open the hood to check if the fan isn't spinning, and inspect the relevant fuses in the fuse box; if the compressor makes no sound, you'll need to take it to a professional repair shop. Driving on the highway in summer can get extremely hot, so don't push yourself—opening the windows for some airflow might help.
When the car's air conditioning fails to cool or blow air at high speeds, common causes include a faulty fan motor, refrigerant leakage, or compressor issues. High-speed engine heat intensifies, and if the fan doesn't operate, poor heat dissipation affects the cooling cycle. Blocked air ducts or malfunctioning dampers can also result in no airflow. Simple components like fuses should be checked and replaced if necessary. If the issue persists, seek professional diagnosis. High-speed driving poses significant risks, so timely resolution is crucial.
