What Causes No Airflow in the First Three Gears of a Car's Air Conditioning?
3 Answers
Reasons for no airflow in the first three gears of a car's air conditioning are as follows: 1. Evaporator Box Air Leak: If there is an air leak at the connection between the evaporator box casing and the air duct, the cold air that should be released from the air conditioning vents continuously leaks from the gap, resulting in reduced airflow from the vents. 2. Air Filter: The air filter is located at the intake of the blower. All cold or warm air blown by the car's air conditioning must pass through the air filter. However, the air filter is prone to accumulating dirt. If the owner does not replace the air filter in time, a large amount of dust can accumulate on the filter, which naturally reduces the airflow passing through it. 3. Poor Sealing of Air Ducts: The air conditioning vents are connected to the blower via additional air ducts. If the sealing of these ducts deteriorates, air leakage occurs, reducing the airflow from the vents.
I've been driving for over twenty years and have encountered the issue of no air from the AC's first, second, or third speed settings a few times. The most common cause is a faulty blower motor resistor, which controls the airflow at low speeds—when it fails, it results in no air at the lower settings. A blown fuse is another frequent issue, especially during summer when the current draw is higher. Check the fuse box near the passenger seat, locate the fuse labeled for the AC fan, and replace it if it's blown. The fan motor itself might also fail completely, requiring professional replacement. A dirty air filter can block the vents, though it usually doesn't stop airflow entirely—regular cleaning is recommended as a preventive measure. Safety first—don't force the car to run; get it fixed promptly to avoid delays and discomfort.
My old car had the same issue last year, the AC had no airflow at low speeds and could only blow at the fourth setting. After searching online, I found that many car owners encountered blower motor resistor failures—this component controls the fan speed, and once it burns out, the low speeds stop working. I tried fixing it myself by first checking the fuse in the glovebox fuse box and replacing it with a new one, which solved the problem easily and cheaply. However, if the fuse isn’t blown, you’ll need to inspect the fan switch or check for loose/corroded connectors. Remember to turn off the engine to avoid electric shock. For prevention, keep the interior clean and minimize using the recirculation mode to reduce dust buildup. Get it fixed as soon as possible—don’t end up like me, overheating on the highway in summer.
