Need help from AC Pro with your compressor? Look no further. This guide will act as your cheat sheet for everything you need to know.

  • The A/C compressor is the most important part of your air-conditioning system – it’s what allows the air conditioning cycle to work.
  • All compressors work in the same way – changing the refrigerant from low-pressure to high-pressure and circulating it.
  • If your compressor isn’t working, you probably need more refrigerant. Use our AC Pro gauge to check your refrigerant levels.

What is an A/C compressor and how does it work?

The A/C compressor is often considered as the heart of a vehicle’s air conditioning system - it’s the most vital component. The compressor pulls the refrigerant out of the evaporator and pushes it into a condenser, and then back into the evaporator to complete the cycle.

It’s an electro-mechanical pump, driven by a belt that’s attached to the engine’s crankshaft – some newer versions can be driven by electricity. This pump moves the refrigerant through the continuous loop of the air conditioning system. The refrigerant is carried by rubber hoses and aluminium pipes from one component to another.

There are various types of compressors (including piston, wobble plate and scroll) used in automotive air conditioning systems, but they all work to accomplish the same objective – transforming refrigerant from a low-pressure vapour to high pressure, high-temperature vapour and circulating it through the A/C system.

Compressors can fail for many different reasons: bad fuses, wear and tear, age, a wiring problem, improper maintenance or even a broken A/C switch in your dashboard. Keep in mind, A/C compressors are designed to only come on when there is enough refrigerant to compress. So, if your compressor is not running, that could be a sign that it is working as designed, and simply needs more refrigerant.

Most systems have a low-pressure safety cut-out that will disable the compressor if there isn’t enough refrigerant in the system. The first thing you’ll want to check is if your compressor is engaged.

How can I tell if a compressor is engaged?

If the compressor is engaged, the centre of the compressor clutch will turn with the outer pulley (please note that on variable displacement compressors the centre of the pulley can be spinning at all times).

Check out our video showing a properly running compressor. If you have specific questions about your AC Pro compressor, please consult a professional certified A/C mechanic.

How do I recharge my A/C system?

If your compressor is functioning properly, you can check your refrigerant using an A/C Pro gauge to determine if low refrigerant levels are at the root of the problem. The following video will guide you on how to use A/C Pro and the steps needed to check refrigerant levels and recharge your A/C system.

If you do run into any questions about how to use A/C Pro or would like additional help, don’t hesitate to contact the pros.