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Car Air Conditioning Not Working – Why It’s Happening and How to Fix It

If the air conditioner in your vehicle doesn’t keep you cool anymore, you might be in for an uncomfortable ride even on a relatively mild day. Unfortunately, the problem might not stop there. Some air conditioners can malfunction in such a way that they blow out hot air. There are a few possible solutions to this issue, and it might be a good idea to schedule an appointment with a qualified professional to get your car in working order once again.


Our guide will take you through the two most common types of problems car air conditioners exhibit, what the symptoms of these problems are, and some tips that might help you.

The Air Conditioner is Blowing Hot Air

If your air conditioner seems to be working but not blowing cold air or seems to be weak, a leak in the refrigerant, a problem with the compressor, or interference with the climate control sensors might be the issue. If one of these features is not working properly, you might get hot air from the vents of your car even when the air conditioner is on the highest setting.


Refrigerant Leak

Refrigerant is the fluid that the air conditioner in your car uses to keep things cool. This fluid turns to vapor when it hits a low-temperature threshold and allows the air to cool off before it reaches your car’s vents. If you have a leak somewhere in the refrigerant’s line, it won’t be effective at making sure the air is cool before it reaches your cabin.

This kind of thing tends to happen more frequently on older vehicles. That’s because the rubber seals that keep everything in place will experience wear and tear over time and lose some of their effectiveness. One of the big problems with this issue is that it can have multiple sources. The hoses, compressor, evaporator, or a combination of these parts may be at fault. That’s why it’s important to have your car’s air conditioner checked by professionals who know where to look.


Your air condenser is at the front of the conditioner and thus susceptible to debris from the road that might damage it. If the pipes in the air conditioner rub up against other components, the friction can cause wear that can lead to leaks.


Diagnosing a Leak

You might be able to detect the presence of a leak just by listening to the compressor unit. When you turn on your car’s air conditioner, you should be able to hear a clicking sound in the engine area. That sound means the compressor’s clutch is engaging with the system. If the system doesn’t have enough refrigerant, the compressor will go through cycles repeatedly and quickly as it tries to compensate. In some cases, refrigerant levels may be too low for the compressor to engage at all.

Some things a qualified air conditioner technician might do to check for a refrigerant leak include:

  • Listening for any hissing noises
  • Looking for oil residue around the fittings and hoses
  • Inspecting the parts for damage
  • Using a special tool to detect the presence of refrigerant


The repair technician will either replace the parts that are causing the issue or recharge the whole conditioning system depending on the severity of the problem. Please note that refrigerant is dangerous and you should schedule an appointment with qualified professionals who can make these repairs safely.


Climate Controls

The knobs and buttons you can use on the front of your car’s air conditioning interface make up the climate controls. These buttons are connected to a system of wires that send signals to tell your car what kind of air and how much of it to blow into the cabin. One of these controls or its supporting parts could fail for a variety of reasons. If you start to notice inconsistent or poor performance from your air conditioning unit, a technician can check to see if it is a climate control problem. Again, because of the complex nature of this part of the system, we stress that you should get in touch with automotive repair services in your area to fix the problem.


The Compressor

Your car’s air compressor is a bit like the main part of the air conditioner. It is responsible for moving refrigerant through the car and turning it from a low-pressure gas into a high-pressure one before it reaches the vents. If your compressor starts acting up, it won’t be able to move refrigerant as reliably as it did before. This problem could lead to warmer air in the car or no air at all.


Fixing the Compressor

If your compressor is not working, it could be an issue with the circuit or the belt. A mechanic can check the power supply that goes to your compressor and see if it is functioning properly. If the belt and power supply turn out to be okay, your technician may need to replace the unit. Don’t be surprised if the mechanic recommends flushing the system to remove any metal shavings that could have damaged other parts of your car. If the professional discovers that the power supply is at fault, it could be due to one of the following things:

  • Faulty fuses or wiring
  • Bad modules or switches
  • Excessively low or high refrigerant levels
  • Temperature or throttle sensor issues


The Vents Don’t Blow Air

The air conditioner’s blower creates airflow and directs it through the dashboard and out the vents. Your car may have an issue with the blower motor itself or some of the flaps that direct the air through particular passageways.


Blower Motor Problems

This motor is a fan that sends air to the passenger compartment of your vehicle. If the motor ceases to function, you won’t feel any air coming out of the vents. It is also possible that the system directing the motor is at fault. There are a few systems that might control the operation of your car’s blower motor, and each of them may require different solutions to fix. We’ll take you through the most common systems in the sections below.

Cable Systems

Cable systems use levers, knobs, flaps, and at least one cable to control the operation of the blower motor. If you move the lever, the cable that attaches to it will open or close the flap as needed to change the direction of the airflow. A broken cable is the most common type of issue with these systems.

Vacuum Systems

These systems utilize vacuum hoses to control the diaphragm and open the flaps that direct airflow. You may have mechanical or electronic controls for this system in your car. One of the most common problems with these systems is a leak in the vacuum seal. You might be able to detect a leak in this system if air stops coming out of the vents when you accelerate your vehicle.

Electrical Systems

Many modern cars include systems that use electric motors to change the position of the vent flaps. A control panel will send a tiny electrical charge to the motor and direct it to open or close the flap as needed. Your vehicle may experience a problem with the motor or the control unit that sends the signal to it. A qualified automotive specialist has the skills necessary to diagnose and fix these issues.


Keep Your Car out of the Shop and on the Road

As you can see, many of these issues require the services of qualified experts like those at Mac’s Automotive Service & Radiator Repair Shop. Mac’s serves the areas of Beaverton, Bend, Boise, Eugene, Portland, and Salem. Please call to schedule your appointment today.



Mac's Radiator is the best mechanic to help you with all of your mechanic needs!  Let Macs help you - we are located in 6 convenient locations, for when you need us close to home, or when you're on the road.




Portland, OR      (503) 777-4706
Beaverton, OR  (503) 646-2943
Bend, OR            (541) 382-6963
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Eugene, OR        (541) 344-0253
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