Why Is Your Car’s AC Blowing Warm Air?

woman controlling AC in car

Why Is Your Car’s AC Blowing Warm Air?


Does your car’s air conditioning system feel like it is blowing warm air instead of cold? If so, you are likely experiencing an issue with the AC. We’ll look at the main reasons why your car air conditioner may be blowing hot air and how to troubleshoot the issue.

Knowing what part of the car’s cooling system has gone wrong can help you avoid costly repairs in the future. To get started on understanding why your car’s AC is blowing warm air, let’s break down each important part of a vehicle’s air conditioning system and what could cause issues that result in a blast of hot air coming out from your vents.

How Does a Car’s A/C Work?

Have you ever started your car and given yourself a blast of hot air when you expected cold? If this has happened to you, then you may be wondering why the air conditioning system in your car is blowing warm air.

Before we look into why this could be happening, it’s important to understand how a car’s AC works. A car’s air conditioning system is made up of a few key components, including the compressor, condenser, evaporator, and expansion valve or orifice tube.

The compressor kicks off the cooling process by compressing refrigerant gas until it becomes a pressurized liquid which moves through the condenser—a part that looks like a radiator and removes heat from the hot gas. The liquid then passes through an expansion valve or orifice tube and turns back into low-pressure gas (colder than before). This cold gas enters the evaporator where it absorbs heat from the air passing through it.

The evaporator then releases cold air into the car’s cabin, removing heat and making the interior of your car comfortable for passengers. It is this process that allows a car’s AC to blow cold air into your vehicle’s cabin when switched on.

Most cars’ air conditioning systems are made of these parts:

  • Compressor
  • Condenser
  • Receiver-Dryer
  • Thermal Expansion
  • Evaporator

Now let’s take a look at why your car’s AC system may be blowing warm air instead of cold…

Common A/C Problems

There are several different reasons why your car’s AC system may be blowing warm air. The most common issues include:

An electrical system issue – this can occur when there is an electrical problem in the system, such as a blown fuse or malfunctioning parts in the compressor.

A refrigerant leak – if you have a refrigerant leak in your vehicle’s A/C system, then it won’t be able to produce cold air and will instead blow warm air into the cabin. In this case, you may need to top off the refrigerant levels with an additional charge of refrigerant before running the A/C again.

Obstructions from road debris – debris, like dirt, can get stuck in components of the air conditioner. This not only affects its ability to cool your car’s cabin but can also cause it to blow warm air. In this instance, you may need to remove and clean out any obstructions that are found inside the system.

A faulty condenser – the condenser is an important part of your car’s air conditioning system, as it takes hot gas and turns it into liquid before releasing cool air. If the condenser isn’t working properly, then the car may not be able to adequately cool down the cabin.

Damaged cooling fans – if the cooling fans aren’t working correctly, or they are damaged, then the AC won’t be able to produce cold air and will instead blow warm air into the cabin. This means that you may need to replace or repair these important parts for your car’s AC system to function as it should.

A broken compressor – if the compressor is broken, then it won’t be able to compress the refrigerant gas and therefore won’t produce cold air. In this case, you may need to have the compressor replaced in order for your car’s AC system to blow cold air again.

Blend-Air door is stuck – The blend-air door controls the temperature of the air in your car’s cabin. If this is stuck, then it won’t be able to regulate the temperature and you may experience a blast of hot air instead of cold when switching on the AC.

What to Do If Your Car’s AC Is Blowing Warm Air?

If your car’s AC system is blowing hot air on a warm or humid day, it’s best to take it to your mechanic immediately. They will use their expertise to identify the problem and provide a solution to fix it. Soon enough, you can enjoy cruising around town with cool air blowing in your face.

Schedule an Appointment with Keith Schulz Garage

Our expert technicians can help you with any issues your car may be having. We’ll get you back on the road in no time! Contact us today!