During the hot summer times, there is no better feeling than entering the car and blasting the AC at its max, after a sweaty grocery run. Things cannot get much worse than sitting in a car with no AC on the sweltering summer days. What if your AC is busted? What could be the reason for the car AC not working?
It could be frustrating when the AC is not in working condition when you need it the most. Whether you need to blow cold air or warm air, the importance of having a working AC in your car when you need it the most is a godsend. We often take the AC in our for granted. We do not understand the crucial role it plays until the car AC is not working.
Having a busted AC can also turn out to be a safety hazard. There is much more to it than comfort. When you keep your car parked under the direct rays of the sun, temperatures inside the car could spike much more than the environmental temperature. Due to the importance of the AC system, almost every car manufactured today is equipped with one.
There can be many reasons why your AC is not working. Sometimes these problems require professional help and can cost hundreds of dollars. But some of these issues aren’t that significant, and you can fix it yourself and save a few bucks.
How Does A Car AC Work?
A car AC system works similarly to a home or office AC system. A common misconception about how the AC in your car works is that it creates cold air and it blows it at you. In reality, a car AC works by removing the heat and moisture that is already inside the vehicle.
The AC controls the airflow thus controlling the temperature. Only by regulating the airflow can the AC maintain an accurate temperature. I further ensure that there is no humidity in the air inside the car.
By doing this, the AC unit enables to drop the temperature down, or increase it when needed. It allows you to defrost your windshield, allowing you to get a clear view.
Understanding how the components in the AC system works will further allow you to understand the entire process, and get an idea of what components are failing when your car AC is not working.
The entire system comprises 6 systems. They are the refrigerant, the compressor, the condenser, receiver-dryer, thermal expansion valve, and evaporator.
Although it is not exactly a component of the AC in your car, it is the lifeline of it.
If the temperature and the pressure are low, it takes a gaseous form. When the temperature and the pressure are high, it takes a liquid form. According to the environmental condition, the state of the refrigerant changes. Every vehicle has a set amount of this gas.
The compressor is a major component of the AC unit. It is a pump that is attached to the engine’s crankshaft, which drives it by giving it power.
As the name suggests, the job of the compressor is to compress. The refrigerant enters the compressor as a gas, at low pressure. When you turn on your AC, the compressor starts to work and the refrigerant starts to compress. The job of the compressor is to compress the refrigerant and increase its pressure.
Under a high-pressure, the gas is pushed into the next, component which is the condenser.
Again as the name suggests, the condenser’s job is to condense the refrigerant that comes in from the compressor. It condenses due to the rapid cooling of the incoming hot air.
The moisture from the hot air turns back into a liquid inside the condenser. This is one of the most recognizable parts of the modern AC system. At this point, the refrigerant turns from a gas to a liquid.
This liquid refrigerant then cools inside the refrigerant by a series of tubes that are running around flowing with cold air. At this point, the refrigerant turns into a high-pressure fluid.
This is the component that acts as a reservoir to the fluid coming in from the condenser. From this reservoir, the fluid is then transferred to the next component which is the evaporator.
Inside this reservoir, there are desiccants. What these desiccants do is, attract water molecules from the liquid that is present. By doing so it attracts the moisture and dries the liquid in the process.
Removing water particles at this stage is essential. Failing to do so at this stage, will turn the water particles into ice crystals. Having ice crystals in the system at this point could end up being a fatal issue for the AC system. Therefore this component plays a huge role to safeguard the entire system.
5. Thermal Expansion Valve
At this point of the AC journey, the refrigerant which is a liquid this point expands thus reducing its pressure. It is another step to turn the liquid into something more accessible for the next component, which is the evaporator.
The valve is also designed in a way to sense pressure, thus it is capable of managing and regulating the refrigerant flow.
The is the main part of the AC unit. It is situated in the cabin, at the passenger side dash. All the other components reside in the engine bay. The design of the evaporator has a similar design to the radiator. But it is a bit smaller and has a few additional components.
The refrigerant enters into the evaporator as a low-pressure liquid and freezes to zero degrees. Since the refrigerant is not water and does not contain any water at this point it does not freeze into a solid.
The evaporator is also in charge of absorbing the humidity from the cabin.
7. Entire Process
All these components come together to form the air conditioning unit of your car.
At the compressor, the refrigerant is compressed. Here it is compressed and turned to a liquid which is then sent to the condenser through high-pressure lines. The condenser allows the liquid to mix with the atmospheric air, thus bringing it back to room temperature.
Then it flows to the expansion valve, where it turns back to a gas. Then it flows to a desiccant bag in the receiver-drier, where all the water particles are removed. Finally, it flows to the evaporator through the tubing where it cools the warm air that is absorbed from the cabin and circulates back as cool air.
Importance Of An AC Unit In Your Car
In the past, air c condition for a car was considered more of a luxury than a necessity. Times have changed, and today you rarely see a car without an AC. One of the main reasons for this is that people today have understood the importance of AC.
Even if you are someone who lives in an area where the climate is not too warm or too cold, you are going to need an AC. You might think that you do not need to change the temperature as it suits you best. But sooner or later you’ll be ending up blasting the AC. Even if the environmental temperature is optimal when you are driving in the city, you cannot drive with the windows down. Due to the sheer number of vehicles on the streets in the modern-day, you’d be inhaling a ton of poisonous fumes.
Having the windows rolled up poses a new challenge. You will not have proper ventilation inside the cabin. Here again, the AC plays a huge role in circulating the air and ventilating the cabin. Also, the air is much cleaner than the air that you’d be taking in if you rolled with the windows down since the unit absorbs a lot of impurities.
Another huge advantage that air conditioning offers is demisting the windshield. This reduces the risk of being in an accident. By reducing the overall exhaustion of the drier, the AC proves to play a huge role in the safety of the drive.
Since the AC allows you to drive with the windows closed, it makes the car more aerodynamic. Even though most people believe that AC takes up a lot of fuel, in reality, it makes the car more aerodynamic. By reducing the drag it increases the efficiency thus saving fuel.
Why Is Your Car AC Not Working?
There are a few symptoms that you could be on the lookout for, that will warn you when your AC is about to fail. By identifying these symptoms, you can ensure that the AC unit suffers the least amount of damage and you can repair it before it totally fails. Here are a few common symptoms that could indicate that your AC is failing.
1. Car AC Not Working – Leaks
With time the condenser in your car will start to leak. The cause could be either age or damage. Depending on the size of the damage and where it is situated, the refrigerant can start to leak. If the leak is big enough or if it is allowed to continue for a long time, you could end up losing all your refrigerant.
One of the best ways to find out, whether there are any leaks is by using a UV AC leak detection kit. The kit uses a dye in the system along with UV light to detect leaks. If the refrigerant is too low, or the compressor is not working this method will not provide results.
Another reason why there could be leaks is that the fitting could be loose. Inspect the hose manifold at the compressor and check whether all the hoses are properly tightened.
If leaks are present, eventually all your refrigerant will run out. After this happens, your AC will completely fail.
These are among the most common symptoms of a failing AC. Identifying them early, and taking necessary action towards fixing the AC.
2. Car AC Not Working – Loud Noise
When the Heating, Ventilation, and Air Conditioning system, which is also known as the HVAC is operating it makes a louder than usual noise when it is kicking on and off. This could indicate a potential problem in the AC compressor.
The compressor contains multiple bearings. If any of them are worn off or broken, you will hear loud noises from the AC unit.
When you turn on the AC and hear rattling or banging or any other unusual noises, that could mean that there is something seriously wrong with the hardware. If the bearings are worn out you will hear a squealing sound. If the compressor’s clutch has failed you will hear a rattling sound.
Continuing to use the AC while it is emitting unusual noises could make a bad situation worse. It is best to take it to a mechanic and get it inspected.
3. Car AC Not Working – Significant Reduction In Cooling
This is one of the most common and early symptoms of a failing AC. Even though you might have cranked the AC to its lowest temperature, you will not get enough cooling. If the condenser suffers any damage that will significantly affect the refrigerant flow. If the refrigerant is not flowing properly, it will affect the cooling efficiency of the AC.
Also, make sure that the condenser and the radiator or working properly. If the condenser or the radiator is blocked by a lot of debris, or if it is damaged, then the cooling will drop down as well.
These are among the most common symptoms of a failing AC. Identifying them early, and taking necessary action towards fixing the AC.
4. Car AC Not Working – Water Dripping On The Floorboards
In the heater coil located under the dashboard, bacteria start to build up with time. The bacteria from the airflow mix with the condensation from the coils and create some sort of slime in the AC fins. When this film builds up in high amounts, it can clog the drain line.
The drain line is a rubber hose. It begins in the evaporator heater box, and goes through the floor and then through the undercarriage to remove moisture. Once plugged, the heater plug fills up, and water drip onto the floor.
The only way to solve this issue is by identifying where the leak is originating and replacing the hose if necessary. You would have to take your car to a technician to get the job done.
5. Car AC Not Working – No Air Coming From The Vents
There could be several reasons if there is no air coming from the vent. And most of them are regarding the blower motor and or electrical malfunctions. The mechanic would have to assess and eliminate all possibilities until he finds the exact cause of the issue.
One of the main reasons that your AC might not be blowing air is due to an electrical issue. If your blower motor does not get power, it cannot blow air. Something as small as a blown fuse or bad relay could cut the power to the blower motor, thus a malfunctioning AC.
Another possible issue is that the blower motor itself or the blower motor regulator can be damaged. If the blower motor resistor is damaged, you will no longer be able to control the airflow. Sometimes it could get stuck at a particular level blowing that exact amount of air, or it could cease to blow air at all. A busted blower motor fan could also be the cause, why your blower motor is not blowing air.
There are 2 air intake areas connected to the AC. They are, the vents that are at the bottom of your windshield and the vent which circulates the air in the cabin. If either one is blocked, your blower motor will not be able to blow air at you.
If it’s a blown fuse or relay, you do not need an expert to solve the issue. You can replace them yourself. If this doesn’t solve the issue you would have to get your AC checked by an expert.
6. Car AC Not Working – Rapid Change In Temperature
While driving if your AC is set to comfortably cool temperature, but suddenly spikes to boiling temperatures, then you know that there is something gone bad in your AC. In this case, there are 2 possible causes.
One possible cause is the thermal expansion valve. Since it is in charge of sending the appropriate amount of refrigerant a failure at that point could cause a sudden spike in temperature. If the sensor in the valve fails it will not send the appropriate amount of refrigerant to the condenser.
Another possible cause is also connected to the thermal expansion valve. This is time, it could be due to a clog in the valve. If moisture is present when the refrigerant enters the thermal expansion valve, it is possible for it to freeze, blocking the valve and the refrigerant flow with it. This could also cause a sudden spike in the temperature.
The only way is for a technician to check the pressure and assess if there are any blockages in the system.
No matter which above symptoms you are facing, it could mean that your car AC is under some serious problems, or it is totally broken.
How Much Is It Going To Cost To Repair If Your Car AC Is Not Woking
An AC repair could be simple as switching a fuse or as costly as switching a compressor. Similar to the damage aspect, the make and model of the car can also dictate how much you’d be spending if your car’s AC is not working.
The AC compressor is the most common component that breaks or malfunctions and results in a broken car AC. While other components do fail, it does not fail as regularly as the AC compressor. Since the AC compressor is a major part of the entire unit, when that fails the cost to repair the AC could also go up.
A common minor AC compressor repair could cost anywhere from $170 to $730 on average. While a major AC compressor repair or if your car needs a complete AC compressor replacement, it could end up costing between $1000 and $4000.
If your AC requires a recharge then the cost will not be as much. It is one of the cheapest AC repairs. An AC recharge will only cost around $100 to $140 (you can cut corners by learning how to charge AC system).
If a hose that is connected to the thermal expansion valve, or any other hose that is running refrigerant is leaking you would need a replacement. An AC hose replacement costs about $500.
If your AC compressor clutch fails, expect to pay about $250. A blower motor replacement will also cost you somewhere along the lines of $250.
As you can see, if your car AC is not working, the repair could cost as little as a hundred bucks or blow a $4000 hole in your wallet. It all depends on the damage that your AC unit is suffering from.
Car Air Conditioning Troubleshooting: Facts
- Common causes of broken air conditioning are leaks or compressor issues.
- If the air blows cool but not cold, the problem could be a clogged filter, cooling fan problem, or radiator trouble, or it could simply need a recharge.
- You can diagnose your car’s AC problems yourself and save money by following a guide.
- The cooling fans on the condenser or radiator should be checked for any restrictions like leaves, bugs, or dirt that would prevent air from passing over the condenser.
- The cabin air filter should be checked to ensure it is not clogged (thus, it’s worth understanding how to replace cabin air filter).
- A manifold gauge set is recommended to check pressures in the system to diagnose an air conditioning issue.
- The AC compressor should be checked first and if the clutch is engaging and disengaging, it is a sign of low refrigerant.
- Leaks are the most common problem associated with air conditioning systems, and using a UV A/C leak detection kit is the easiest way to find a leak.
- AC components that can fail include the compressor and clutch, accumulator/drier, orifice tube/expansion valve, condenser, and evaporator core.
- Inspect and test before replacing any AC component, ensure refrigerant levels are correct, and the radiator/AC condenser fan(s) are working properly.
Verdict – Car AC Not Working
When you think about the car AC it is not as important as the engine, transmission, or any other major component of a car. Nonetheless, it is still a component that completes the car. Whether you know it or not, it plays a huge role in the comfort and the safety of your drive.
A car AC consists of many major components. Each of them is just as important as the other to make sure that your car AC works perfectly. If one of these components fails, it could result in your car’s AC not working.
There can be one of several causes that ends up affecting the functionality of the AC. If you can spot the symptoms early and get them repaired as soon as possible you can reduce the damage as much as possible. Depending on the component that is damaged the repair cost of your car’s AC is not working can vary. On average, considering every kind of AC repair, it costs $235 to fix if your car AC is not working.
These tools have been tried and tested by our team, they are ideal for fixing your car at home.
Thanks for the suggestion to have your air conditioning checked by a professional if they blow out warm air. I never knew that these are problems that a faulty component could cause. Since I do plan to purchase a car someday, this information can definitely help me someday.