For people who live in hot climates, the air conditioning in the car is definitely a blessing.
While many people take car air conditioning for granted, its importance is clear when the air conditioning fails or the compressor is damaged.
There are some common symptoms of a bad AC compressor switch and some simple repairs for them. Let’s look at the most common symptoms.
Faulty AC Compressor Clutch Symptoms
The AC compressor is the most integral part of the air conditioning system and is responsible for pressurizing the refrigerant and distributing it. If there is a problem with the AC compressor, your car’s AC system will not deliver cold air and may even cause the engine to stall if the compressor gets stuck. There are many reasons why your car’s AC compressor can fail, and in this article, we will discuss these symptoms.
1. AC Blowing Hot Air
One of the most obvious symptoms you will notice is that the car’s air conditioning system is no longer blowing cold air. The reason for this is that the damaged compressor does not distribute the refrigerant effectively, which means that the air conditioning system no longer blows cold air.
2. Compressor Making Weird Noises
The AC compressor is a complex component and has a number of internal components that perform certain functions. If the compressor is damaged, the internal components are also affected and start to produce different types of noise. For example, worn bearings can produce a squeaking or grinding noise. The best option, in this case, is to replace the entire compressor.
3. Refrigerant Fluid Leaking
The vehicle AC compressor has a built-in bearing, and these bearings prevent the liquid from escaping while the refrigerant is pressurized. However, when the AC compressor gets old, these bearings are damaged and as a result the fluid starts to leak through them. In such a case, you will see liquid leaking near the compressor, indicating that the bearings are worn out.
4. Faulty Compressor Clutch
The compressor clutch regulates when the AC compressor should be switched on and off. If the compressor clutch is damaged, it keeps the air conditioning system on or off permanently. A defective compressor clutch can be replaced, but it is generally recommended to replace the entire compressor to save time and additional costs.
How to Diagnose if the Car AC Compressor Has Failed?
If you are experiencing the above symptoms, there is a high probability that your car’s AC compressor has failed. To be on the safe side, you should take some diagnostic steps before you finally conclude that the compressor needs to be replaced.
1. Turn on the Air Conditioning
The first thing you should do is turn on the car’s air conditioning and check whether the fan is blowing cold air. If not, there is some sort of problem with the air conditioning.
2. Inspect the Compressor
Next, open the hood and visually inspect the AC compressor for signs of damage, rust, leaks, etc. Any visible damage is an indication of a defective or malfunctioning AC compressor. Also, the compressor will not work properly if there is not enough oil, and may even cause the temperature in the vehicle to rise.
3. Inspect the Serpentine Belt
If you have inspected the compressor and cannot find any damage or rust, the next step would be to check the belts to make sure they are in good condition and have no cracks. A worn belt can cause damage to the compressor, so it is advisable to replace it as soon as possible.
4. Check the Compressor Clutch
The clutch is located in front of the AC compressor. Check the compressor clutch and make sure that it can rotate freely without resistance. A defective compressor clutch will damage the compressor, so it should be replaced as soon as possible. You can try to switch on the AC compressor manually.
5. Check if the Compressor Starts
To check if the AC compressor starts, start the engine and set the AC fan setting to max. Open the hood and see if you can hear the sound of the compressor. If the compressor does not start, you will hear a funny nose.
6. Check for any Refrigerant Leak
The refrigerant in the AC system should not be low, nor should it leak. If there is a leak, the AC performance of your vehicle will not meet requirements, and the best way to detect a leak is to use an electronic leak detector.
7. Check if there is any refrigerant pressure in the AC system
Check if there is refrigerant pressure in the AC system using an air conditioner that does this job for you, or you can check it manually by using a pressure gauge. You should have about 14 bar on the high-pressure side and 2.5 bar on the low-pressure side when the AC compressor switch is pumping and working. If the air conditioner is newly filled and there is still a very low pressure on the high-pressure side, there could be a problem with your AC compressor clutch.
How to Manually Engage the AC Compressor Clutch?
To test if the AC compressor switch is working properly, you can turn it on manually with some simple tools. You can do this at home.
1. Give it a light tap with a tool
An easy way to check the clutch of your AC compressor is to gently and lightly tap on the clutch when the compressor is running and the motor is on. Sometimes, when the clutch is worn, the disc is too thin and may not engage properly. This must be done very carefully so that you do not get your tool stuck in the snake belt and ruin your engine, which could result in serious damage. This is only recommended if you have a great deal of knowledge about it. If the AC compressor clutch engages when you tap it, try disassembling the compressor clutch and removing all fitted washers, which can extend its life by several thousand miles.
2. Remove the connector and force it with 12v and ground.
The AC compressor clutch often has a plug with 2 pins. One is for ground and one for the 12-volt power cable. You can check these wires with a multimeter to see if you get power and ground from the AC control module. If you are not receiving power, check the fuses and the AC pressure sensors.
You can also take long wires from the battery + and – and try to manually operate the clutch of the AC compressor in the plug. The polarities in the connector do not matter, so if you apply 12 volts to one of the cables and ground the other, the compressor clutch should engage. If it does not engage when manually engaged, replace the clutch.
AC Compressor Clutch Replacement Cost
Repairing or replacing the auto compressor is one of the most expensive procedures and the price usually varies depending on the model and brand. Since the AC compressor has several moving parts, these parts will be damaged over time. Most mechanics and car experts recommend replacing the entire compressor rather than repairing these individual components, as this is less expensive and saves time.
The cost of the AC compressor itself ranges from $200 to $800, while labor costs range from $370 to $1000. Prices can be higher if the car is new or has a complicated unit. The cost also depends on the service garage. For example, an official car dealer will charge you much more than a local mechanic.
How to Save Cost While Replacing Car AC Compressor?
Replacing the AC compressor is expensive work and can cost you up to $1000 to repair. However, there are certain ways that you can save this money, even if it requires some additional work. Most auto repair shops order the car parts from online dealers and sell them at a higher price. To save money, you can visit these retailers such as NAPA, Walmart, and Amazon and order the parts yourself. Compared to car dealerships, you will definitely find the parts at a lower price.
Although you can replace the AC compressor yourself to save costs, we do not recommend this as it is a difficult procedure. However, it is always a good idea to research the market and find the best car dealer and mechanic who does not charge excessive labour costs.
If you have any further questions about car air conditioning, simply comment below and one of our experts will contact you as soon as possible.
Hello I’m Magnus, the owner and the writer of this website. I have been working with cars since I was 16 and I’m specialized with in-depth Automotive diagnostics. Also been driving drifting for the last 6 years. I’m here to give you answers to all your automotive questions and I hope that you enjoy our content.