Car Air Conditioner Not Cooling? (9 Reasons Why)

We all rely on the air conditioner in our cars to keep us cool on those hot summer days. There is no worse feeling than having no cool air coming out of your air vents when it is so hot in the car.

If you turn on your air conditioner and only get warm air coming out of the air vents, then something must obviously be wrong with your air conditioning system. This doesn’t mean the entire system is malfunctioning, though.

There could be just one component of the entire system that is faulty. All it takes is one bad component for the air conditioning system to fail completely. The hardest part is figuring out which component caused this malfunction.

Common Causes of a Car A/C Not Cooling

There are a lot of possible causes for your air conditioner to stop producing cool air for your car. Rather than guessing what it could be, you should understand what the most common causes are.

Here are five of the most common causes that you should consider paying attention to if your car air conditioner is not cold.

See Also: Why Does My Car Overheat When the A/C Is On?

1) Dirty/Clogged Cabin Filter

dirty cabin air filter

When identifying an issue with an AC system, a dirty cabin air filter is one is frequently missed. Dust, insects, leaves, and other different kinds of material can all be caught by this filter. Your air conditioner’s capacity to cool will almost certainly be reduced if air can’t flow as intended.

Fortunately, it’s simple to clean or replace a cabin filter yourself, and is one of the least expensive maintenance procedures you can do.

2) Bad A/C Compressor

bad AC compressor

The A/C compressor is responsible for compressing the refrigerant so that it is highly pressurized. This is what happens before the refrigerant gets pumped into the A/C condenser where it gets cooled down.

If your A/C compressor is not working, then it will not be able to compress the refrigerant. This will ultimately cause the air cooling process to fail completely.

3) Refrigerant Leak

freon recharge

Refrigerant is like the blood of the air conditioning system. When the hot refrigerant liquid gets condensed by the A/C condenser, it produces a cool gas which becomes the cool air that blows out of the air vents.

If you don’t have enough refrigerant flowing through your air conditioning system, then you are not going to have any cool air. Refrigerant leakage is a common reason for a low level of refrigerant in your reservoir.

The location of the leak may be difficult to find. Check the hose connections of the system thoroughly to find any cracks or leaks in them.

Even if there are no signs of a leak, refrigerant can be lost at a very slow rate over a number of years and recharging your A/C system is the only fix.

4) Bad A/C Condenser

car radiator

An A/C condenser is a fancy radiator that is designed to cool down refrigerant instead of engine coolant.  It typically sits at the front of the vehicle in line with the main radiator.

If the cooling capacity of the condenser is exceeded or you have a malfunctioning A/C condenser, then the refrigerant will remain overheated. Then all you will get is a bunch of hot air coming out of your air vents.

5) Electrical Problems

electrical problems

Don’t forget that your air conditioning system is powered by electricity. There are numerous wires connecting your air conditioner to your car battery and dashboard controls. If any of these wires are worn or damaged, then it could interfere with the electrical supply that your air conditioner needs to function properly and produce cool air.

It might be difficult to diagnose this problem on your own because you might assume that your entire electrical system is compromised. But if all your other electrical components are functioning, then you will need to conduct a visual inspection of the wiring to see where the problem is.

If you are not confident in this task, then it may be a better idea to hire a professional mechanic to do it for you instead.

6) Bad Accessory Belt

bad serpentine belt symptoms

If you have a bad air conditioning or accessory belt, the compressor may be unable to spin off the power from the crankshaft. If the compressor isn’t spining, you won’t get any cool air. Inspect the belts on your car to make sure they are good and there is no slippage while the air conditioner is running.

If you aren’t running the A/C, it may look like your compressor isn’t spinning even though the belt around the pulley is turning. This is because the compressor has a clutch that stops spinning when you’re not running the A/C. When you turn on your A/C, this clutch engages and you will see the compressor start spinning.

7) Bad A/C Clutch

serpentine belt squealing

Clutches wear out over time, and the clutch in your A/C compressor is no exception. If your A/C clutch goes bad, you might notice a burning smell coming from the engine bay when you turn on your air conditioning. You might also hear a squeal as the clutch tries to engage and then begins to slip.

8) Blown Fuse

fuse box

Checking fuses is a quick troubleshooting step that is often overlooked. If your vehicle blew a fuse, you may not even have power going to the air conditioning components. Fuse boxes are commonly found in the engine bay and in the footwell of most vehicles.

If you find a blown fuse, replace it, and the fuse pops a second time, you have an electrical issue. Fuses commonly blow due to an electrical short that sends too much power to a component. This can happen if the insulation is worn around part of the wiring harness. Another common cause of blown fuses is jump starting the vehicle incorrectly.

9) Your Heater is On

turn on heater

This may sound obvious, but running the heater will blow hot air, even when you’ve pressed the air conditioning button. Since the air conditioner dries out the air, running the air conditioner and the heater at the same time is a great way to get nice, dry air in the wintertime. This is especially convenient if you live in rainy or humid environments.


3 thoughts on “Car Air Conditioner Not Cooling? (9 Reasons Why)”

  1. The is vaccum and no leak detected in the system. when rechanging the refrigant, less amount of the refrigant 10 oz then is reads the system is over charge. Both manifold gauges (low & high) are at 100 PSI.


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