Our Generation Florida

Air Conditioning Trouble

By Jason Gaschel

QUESTION: My air conditioner is not cold enough at idle sitting at a stop sign, but gets colder when I get on the freeway. Is this a sign that my compressor is weak?

Jason’s Reply:  Living in Florida, the air conditioning system is used a lot more frequently than in northern climates. Your problem is a very common one, but does not necessarily indicate that the compressor is weak. The air conditioning system relies on airflow through the condenser to exchange the heat from the system. The condenser is located in front of the engine’s radiator where a strong flow of air can remove heat from the high pressure refrigerant. This heat was absorbed from the interior of the vehicle. Just like the engine’s radiator, the condenser uses the vehicle’s fan to generate airflow across the tubes and fins to remove heat from the system. These tubes and fins increase the surface area of the condenser and help dissipate heat more efficiently. When the A/C system is turned on, the vehicle’s computer automatically turns on the cooling fans to help remove heat faster. A faulty cooling fan will cause a vehicle to cool ineffectively at low speeds or sitting at a stop sign. An easy way to check would be to listen for the fan to come on when you turn the A/C on with the vehicle running. If you don’t hear the fan engage, then you have found the problem.

Another cause could be if the vehicle sucked up a plastic bag or has road debris partially blocking the condenser. This would also restrict airflow and not allow the heat to be removed as efficiently from the system.

The fact that the system cools while going down the road at highway speeds leads me to believe that the problem lies in the cooling fan system. A faulty fan, fan control, or wiring could be the culprit of this problem. A full system inspection would not hurt either, as this system is vital for comfortable driving in Florida.