What Should You Do When Your Car AC Compressor Not Turning On?

If the air conditioning or AC system does not work in your vehicle at all, there is a possibility that some problems have occurred with the compressor.

Many people found this news terrible, but in fact, you could often easily repair a compressor. Before making any final decisions, you need to perform a little troubleshooting and try to find out the source of the issue.

Bear in your mind that there are only so many things for a daily homeowner to do in this matter. Therefore, most of the tests should be done or handled by professional and experienced mechanics.


What is a Car’s AC Compressor?

In most car models these days, an air conditioner could not work correctly without an operating compressor. In many standard residential AC systems, a compressor is often placed in the outdoor area.

As its name suggests, the main function of a compressor is definitely compression.

In an air conditioning system, this part operates by compressing gaseous, low-pressure, and cool refrigerant till it becomes hotter and gets a much higher amount of pressure. After that, it squeezes the gaseous refrigerant into a condenser.

When the refrigerant is still locating in a compressor, it is often seen as the beginning part of an air conditioning cycle. If an AC compressor could not turn on, this process could not begin.

Check for The Power​

The first and also the most necessary thing to do when an AC compressor does not work is to ensure that this unit is still receiving power. In some cases, a fuse would be blown or a breaker would be tripped.

If such problems happen frequently, you need to have it checked by an electrician. In fact, it is not usual for the breakers and the fuses to experience persistent issues. Constant starts and stops could do a lot of damage to the compressor as well as on an AC system as a whole.



If the breakers and the fuses are still fine, you might just need to call for help from an HVAC (heating, ventilation and air conditioning) technician. The only exception is when you have a multi-meter and know how to use this device. If so, you could apply it to examine and check if the AC compressor is receiving the correct voltage. Even when you are able to measure that, you would nearly certainly want to have an HVAC contractor for the remaining tasks. The positive news is that an issue like this could often be solved without a lot of money and time.

How a Professional Technician Troubleshoot a Problem with The AC Compressor​?

It is helpful for you to understand if the problem of an air conditioning comes from its compressor. In fact, this might not be great news, but it could provide an HVAC contractor something to work on arriving

. It is simple to suppose that you are going to purchase a new device, but this is not always the case. An AC compressor is made with a lot of different parts, and any of them could fail and lead to an issue.

Therefore, a technician who comes to your home would take into consideration the following possibilities, then try to rule out each of these:

  • Capacitor: In many situations, problems in the compressor are mostly originated by broken or faulty capacitors. If the technician finds out that the capacitors are the cause, he might take it out and replace with a hard-start one, which might solve the whole problem. The only way that you would troubleshoot the capacitors is to replace it and test the unit. Thus, this is a common task when the compressor in your AC system does not turn on.


  • Start relay: Just like the capacitors, an HVAC technician might try to replace the start relays, which is probably the sure-fire way to know if it is working correctly or not. If the compressor operates after the installation of a new start relay, the issue would be solved.


  • Valves: A faulty valve could result in major issues in an AC compressor. In general, the most common problem with the refrigerant is that the liquid instead of fuel comes into the inlet of the compressor. In these situations, the compressor might still work, but your air conditioning system would not cool the air. Luckily, replacing a broken valve would resolve this problem.


  • Terminal connection: You should also have a look at the terminal connection to make sure that everything is in the correct place and tight. A loose connection could lead to some pretty considerable issues. If the compressor works intermittently, the problem would simple as this. In addition, there is a possibility that the terminal connection is just dirty, which requires a good process of cleaning to solve.

Dead Compressors

When you know that the compressor in an air conditioning system is definitely dead, maybe you would have two replacement options: the compressor or the whole air conditioner. The main decisive factor would be the cost of replacing a compressor. If it is no more than 50 percent of the amount of purchasing the entire new unit, this is possibly the best choice for you. Otherwise, you should consider buying a new air conditioner for your car.

Related Article: What Should You Do When AC Compressor Clutch Not Engaging?


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4 thoughts on “What Should You Do When Your Car AC Compressor Not Turning On?”

  1. Hi john. i have a question.. I have a 99 chevy venture and im having ac issues. fans work as air is forced in the van but doesnt seem to kick on when i turn the ac on. Ive been googling and watching videos on youtube but i havent found anybody with that particular issue. my question would be can i take the compressor apart clean it and see if any damage is present or do i just need to get a new compressor?

  2. Hello,

    Wondering if you accepted gp on your site. Also would you be willing to insert lk in existing posts?

    How much would you charge for this?



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