Air Conditioning Compressor

Air Conditioning Compressor

An air conditioning compressor is a high-performance pump that forces refrigerant throughout the air conditioning system. It increases pressure inside the system to enhance its performance and efficiency. As a general rule, an air conditioning compressor is driven by a crankshaft via a drive belt, whereas, there are also vehicles equipped with an electric compressor. The latter can be found in just about any modern hybrid and electrical vehicle.

If you drive a traditional vehicle, your belt-driven air conditioning compressor will not be engaged until you press on the A/C button on your dashboard. It is operated and controlled by your engine control unit which will engage the air conditioning compressor clutch with an electrical solenoid in response to a click on the A/C button. On some newer vehicles, an air conditioning compressor functions all the time while the engine is running. However, it can be disengaged by pushing on the ECO button.

The air conditioning compressor is a key part of your air conditioning system, which is why its failure or any irregularities in its operation will cause a number of problems. Here is the list of the most common of them:

Lack of cooling

A failed air compressor will cause your vents to blow warm or improperly cooled air. In some cases, this can be caused by a failing compressor clutch that usually comes as a part of an air compressor assembly.

Abnormal noises 

An air compressor with internal damage can cause a rattling noise when running. This may also cause the drive belt to squeal and, in some cases, even to break.


A damaged or cracked compressor can become a source of refrigerant leaks, which are usually odorless and colorless. They can be detected when exposed to UV light.

Your check engine light is on

Electric air compressors are operated and controlled by an engine control unit. If such a compressor malfunctions, the engine control unit will turn on the check engine light.

Air conditioning compressor troubleshooting

The entire air conditioning system should be properly diagnosed before replacing the compressor or another part of the system. Most compressor failures happen due to a lack of lubrication that is caused by refrigerant leaks.

Since the air conditioning system is filled with a dangerous chemical (refrigerant), its inspection and repairs must be done by a professional. He or she will need to evacuate and recharge the system by means of special equipment when replacing a bad compressor. In some cases, several other system components must be replaced along with a failed compressor if the latter has been the source of metal particles.

Electrical air compressors are especially complex, which is why they must be diagnosed and replaced by trained professionals. Each of them is a part of a high-voltage electrical system that can cause an injury if improperly handled.