There are several reasons why a car's alternating current may not cool down when stopped and only blows when it is moving. The most common reason is that the condenser cooling fan is not working. It is important to know that the radiator and the condenser share the fan several times, on other occasions, two others. The reason that a bad cooling fan can affect the alternating current so much is that the heat from the refrigerant (freon) is normally cooled as it passes through the condenser. Thus, even if the condenser fan is NOT running, AC power may not be affected when the car is traveling at highway speed . This is due to the fact that the air passes through the condenser as it rolls on the road, so the fan is not needed. When the car is at a standstill, the condenser is totally dependent on the fan to cool it down. Sometimes the cooling fan may be running, but it may be that it moves too slowly to cool the condenser sufficiently. To check the motor, a warning light can be used to check if the electrical outlet is powered and grounded. If power and ground are present and the engine is not running, the engine is open. When the cooling fan motor is worn out, it can sometimes be started temporarily by lightly tapping the electric fan motor with a small hammer or wrench. If the fan rotates at all when this is done, it will be necessary to replace the motor. This is just another way to check that it is getting the energy it needs to work. Also keep in mind that a cooling fan can start at any time (some even light up when the engine is off). So be careful not to catch your hand! Note that if the cooling fan motor has seized, it is likely that the fuse has also blown. So, if there is no fan power and the motor is locked, it is very likely that a fuse needs to be replaced when replacing the fan motor.
- The car could overheat, caused by something other than the fan.
- Heat transfer from the radiator to the condenser may impair efficiency if the car is overheated.
- The AC compressor may not pump fast enough (rpm).
- A regulator may not properly regulate the refrigerant.
- The condenser fins may be curved or the condenser may be clogged with foreign debris.
combs for straightening the fins of the condenser. But in my experience, folded condenser fins are not a common problem. A more common problem if you drive in the country, is the pollen accumulated over time between the fins. Waste from the road, such as a plastic bag or piece of paper obstructing a portion of the condenser, reducing performance can occur anywhere. It is amusing to me that during my car technician job, many customers were worried that the air conditioner was not cooling, but did not notice that the car was overheating – even if the temperature gauge was fixed!