Car AC Compressor Clicks On and Off Constantly [Troubleshooting Guide]

Hey there! If you’re reading this, it probably means your car’s AC compressor has developed an interesting quirk – it’s clicking on and off like it’s playing a never-ending game of tag with itself. I bet it’s driving you a bit crazy, huh?

Your car’s air conditioning (AC) system has many parts, but the compressor is like its heart. When it’s working correctly, it pumps refrigerant through the system to help keep you and your car’s interior nice and cool. But, just like any heart, it can act up from time to time.

I’ve had my fair share of this problem myself and it wasn’t a pleasant experience for me at first. But the good news is, it’s often a problem that can be fixed.

So, if your car AC compressor clicks on and off constantly, stick with me. I’m going to walk you through why this happens and what you can do about it from my experience.

Ready? Let’s get started!

Understanding the Issue

Now that you know what an AC compressor does, let’s dig a bit deeper into what’s going on when your car AC compressor clicks on and off constantly. You’re probably thinking, “Is my AC just being extra decisive?” Well, not quite.

Usually, your compressor should only click on when it needs to cool down the car, and then click off when the job’s done. It’s like a really great employee – always doing what’s needed and taking a break when it’s not. But when it’s constantly clicking on and off? Well, it’s more like an over-caffeinated intern – super eager, but not so effective.

This isn’t normal behavior for a compressor and it’s usually a sign that something’s not quite right. Imagine your AC compressor is like a team captain. When it’s not playing the game properly, the whole team (in this case, your AC system) can’t function correctly.

I’ve had some clients tell me that they initially ignored this on-and-off clicking until they found out that their AC had completely stopped cooling. And believe me, there’s nothing worse than being stuck in a car with no AC in the middle of summer!

This clicking sound might seem minor, but it can be a symptom of a bigger issue. But don’t worry! In the following sections, I’ll explain the common reasons why this happens and how you can identify the root cause and get it fixed.

Common Reasons Why Your Car AC Compressor Clicks On and Off Constantly

Alright, you’ve stuck with me this far, so let’s dive into some of the most common reasons for the constant clicking:

1. Low Refrigerant

This one’s a classic. Your AC system needs refrigerant to cool the air. When there isn’t enough, it’s like trying to make lemonade with just one lemon – it’s not gonna work!

The compressor tries to compensate by clicking on and off to try and cool the air, but without enough refrigerant, it’s fighting a losing battle.

2. Faulty Relay

Think of the relay as the messenger for your AC system. It tells the compressor when to start working and when to take a break. Now, if this messenger gets confused, it can send mixed signals, causing the compressor to click on and off constantly.

3. Bad Clutch

The clutch on your compressor is like a gatekeeper, deciding when the compressor should and shouldn’t be working. When it’s faulty, it can make your compressor work overtime, causing that constant clicking.

So, there you have it. These are just a few of the usual suspects. If your car AC compressor is clicking on and off constantly, it’s probably due to one of these reasons. But don’t worry, we’re going to figure out how to fix it next.

Recognizing Symptoms of a Faulty Compressor

Now that you know some potential culprits for why your car AC compressor clicks on and off constantly, let’s talk about some other signs that can hint towards a faulty compressor.

1. Poor Cooling

This one might seem obvious, but it’s worth mentioning. If your AC isn’t keeping your car as cool as it should, it could be a sign that the compressor is not working properly.

2. Strange Noises

If you hear any strange noises other than the clicking on and off, pay attention. Maybe it’s a squealing or a grinding noise. These could be signs that something is off with the compressor. I’ve had a car owner compare the noise to a squirrel trapped under their hood. Strange comparison, I know!

3. AC Blowing Warm Air

If your AC starts blowing warm air while the compressor is clicking on and off, it’s like the AC waving a big red flag saying, “Hey, something’s not right here!”

Now, not all of these symptoms will always show up. But they’re good clues to keep in mind when you move on to the troubleshooting steps.

Troubleshooting Steps

We’ve already identified the usual suspects and symptoms. Now, let’s see how you can investigate further and get your AC running smoothly again.

1. Check the Refrigerant Level

First things first, you need to check if your AC has enough refrigerant. For this, you’ll need an AC pressure gauge. Don’t worry, you can pick one up at any auto parts store.

Attach the gauge to the low-pressure port of your AC system (it’s usually on the largest refrigerant line and is often covered with a plastic cap). The gauge will tell you if the refrigerant level is low.

Now, if it is low, you might be tempted to just fill it up and call it a day. But hold your horses! This could be a sign of a leak, and that’s something a professional should handle.

2. Test the Relay

To test the relay, you’ll need a multimeter (also available at an auto parts store). First, make sure your car is off. Then, locate your AC compressor clutch relay (it’s in the fuse box). Using the multimeter, check for continuity. If there’s no continuity, the relay’s likely faulty.

3. Check the Clutch

This one’s pretty straightforward. With your car off, take a look at the AC compressor clutch (it’s at the front of the compressor). Then, start your car and turn on the AC. If the clutch doesn’t engage (meaning, if it doesn’t start spinning), then it’s not working properly.

These are basic steps you can try at home. But remember, safety comes first. If you’re not comfortable doing these or if the problem persists, please take your car to a professional. You’ve done great detective work up until now, but sometimes, it’s best to leave the final call to the pros.

Fixing the Problem

You’ve done some top-notch investigating! But what good is finding the cause if you don’t fix the problem, right? Let’s talk about what you can do if your car AC compressor is still clicking on and off constantly even after identifying the issue.

1. Recharge the Refrigerant

If your refrigerant was low but there’s no leak, you can recharge it yourself. Most auto parts stores sell recharge kits that are pretty easy to use. If you run into a situation where you have the car AC compressor running but won’t take Freon, you might want to have a deep dive into that post I created.

2. Replace the Relay

If you’ve found out that your relay is faulty, you can replace it. It’s usually as easy as popping out the old one and putting in the new one, like changing the batteries in a remote.

But, make sure you buy the correct relay for your car model. And remember, your car needs to be off before you start playing around with the relay.

3. Consult a Professional for the Clutch

If the clutch is the issue, I’d strongly recommend getting a professional to fix it. Replacing a clutch isn’t like changing a tire. It’s a complicated process that can cause more harm than good if done incorrectly.

In the next section, I’ll talk about how you can prevent these issues from happening in the future. Because an ounce of prevention is worth a pound of cure!

Prevention and Maintenance Tips

So, let’s wrap things up by talking about some preventative measures. Because the best way to deal with a car AC compressor that turns on and off is to stop it from happening in the first place, right?

1. Regular Servicing

This is the big one. Regular servicing of your car’s AC system can prevent a lot of issues. It’s like going to the doctor for a check-up. Better to catch potential problems early, instead of waiting until you’re really sick, right?

2. Pay Attention to Signs

If your AC starts acting weird, don’t ignore it. Whether it’s odd noises, not cooling effectively, or the compressor clicking on and off constantly, these are all signs that something might be off.

3. Keep Your Car in Good Shape

This might seem unrelated, but keeping your car in good shape overall can help your AC. Regular oil changes, keeping the engine maintained, and making sure your car’s electrical system is in top shape can all help keep your AC running smoothly.


I’ve talked about the likely culprits – from low refrigerant to faulty relays, and the tricky clutch, not to mention our troubleshooting steps and preventative measures. Just keep in mind, some problems need professional hands. So, never hesitate to take your car to a technician when things feel overwhelming.

It’s my hope that with this guide, you feel more empowered and less anxious the next time your car AC starts acting up.

In the end, taking care of your car is a lot like taking care of yourself. Regular check-ups, listening to signs, and not ignoring issues can save you a lot of trouble down the line.