How to Troubleshoot a Broken Car AC

A broken AC is one of a car owner’s worst nightmares. Especially in the dead heat of summer! Just because the engine is running, doesn't mean the car isn't drivable! Not only are you completely uncomfortable, but your passengers are as well! That's why you need to learn how to troubleshoot a car AC on your own!

While most AC troubles will require a trip to the mechanic, knowing more about the workings of your car AC unit can be helpful! Before rushing to the mechanic, try these simple steps and ensure that the problem is something that you can’t actually fix yourself. 

Check This: How to Diagnose Your Car’s AC Filter and Quickly Repair It

Step One to Troubleshoot Car AC: Turn on the AC and Verify that it’s Not Working

Before you rush out to buy any supercool AC vacuum products, you need to make sure that your AC is actually broken. That's right, sometimes user error happens. We are all human, it's ok!

Begin by turning the AC all the way up. This means putting setting the temperature to the coldest setting, as well as putting the airflow on as high as possible. This is a basic, but important part of how to troubleshoot car AC airflow!

Car AC's usually have an indicator light, so ensure that the light is on by the time you hit maximum AC. If the light doesn’t come on, it’s either the switch itself malfunctioning, or the AC isn’t getting enough power.

Next, verify that there’s no air blowing in through the vents. If you can’t feel any air, try different speed settings on your AC and see if anything changes. You should also double check to see if the air vents are actually open all the way!

If you only feel air coming in at certain settings, the problem may be with the AC’s blower motor or the blower motor resistor. Sometimes, blower motors and their resistors fail when pushing hot and cold air through the vents.

AC Knob

Step Two: Check the Strength and the Temperature of the Airflow

If you turn on the AC and do feel the air, it’s possible that it’s not blowing strong enough, or cold enough. In that case, you’ll want to feel the force of the air coming out of the vents. Here are a few questions you should ask yourself while checking the air strength and temperature: 

  • Is the air weak on a high setting?
  • Can I feel the air up close, as well as farther away?
  • Does the temperature setting match the air temperature?
  • Is the air too hot, or too cold?
  • Can you feel the airflow in the rear of the car?

By answering these questions, you can begin to narrow down what could be wrong with your AC. If the air it weak at a more powerful setting, you should check your car’s cabin air filter. Ensure that there’s no obstruction blocking the airflow.

You can also check the temperature of the air using a meat thermometer. Stick it in the car’s vent, preferably near the driver’s window, and turn on the AC. The temperature you expect from a car AC depends heavily on the outside temperature.

As a rule of thumb, the car AC drops the temperature 30 – 40 degrees relative to that on the outside. If your car AC is not as cold as it should be, it’s definitely time to get it checked out by your mechanic. You can only troubleshoot car AC units on your own for so long!

Step Three: Look Under the Hood

Once you’re done inspecting the AC from the inside, move your checks outside. Pop the hood and check for any airflow obstructions. Begin from the grill and bumper, as well as the area around the condenser. Double check that there is no debris or foreign objects blocking the flow of air.

Once that is done, you can move to the car’s AC belt. Some cars have a separate belt for the AC. All in all, if your car’s model is like that, then you need to make sure it’s not loose or damaged.

Before you check the belt, ensure that the engine is off and the key is out of the ignition. Push down on the belt with your fingers to see if it’s loose or missing. If it is, place the belt back on the wheel and try the AC again.

It's not as easy as knowing what to do if you lose your keys, or if you need to change your tire. But these small steps can save you a lot of money at the mechanic! 

Troubleshoot Car AC On Your Own to Possibly Save Money!

These simple steps can help you identify minor problems you might have with your car AC. Keep in mind that not everyone is a certified mechanic. If at any point you feel like this may be something you are uncomfortable with, or you can't narrow down the problem, it's a good idea to seek professional help! 

However, if you can use these easy steps to fix your AC yourself, you may be able to save yourself a visit to the mechanic. Not to mention save a few dollars! Just follow these helpful hints and you will be able to troubleshoot your car's AC problems yourself!

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Hanna Embry

As a freelance writer, I have been creating content and writing blogs for over a decade. Not only do I love writing about cars, but I also have experience in many other fields. I have been a guest writer on many popular blogs, as well as ghostwritten novels. When I’m not writing, you can find me with my family, reading a book, or working on an art project.