Why Is AC Not Working In Car & How To Fix It?


AC not working is the most common problem when the car is old. However, there can be many reasons for AC not working in a car, so it is very important to check and then fix them. Because ignoring it for a long time can increase the cost of AC repair.

Various parts are used in a car’s air conditioning system. But in many cars, some part of the AC system gets damaged, due to which the car’s AC stops working. Therefore, you should know the reasons for which the car air conditioning system stops working.

Why is AC Not Working in Car : Causes

If your car’s AC is not working, the main reason is a faulty AC compressor or refrigerant leakage. However, other causes may include a faulty condessor, a dirty cabin filter, a loose serpentine belt, a broken AC pipe, a faulty AC evaporator coil, a bad blower motor, or other electrical problems.

Let us understand in detail the reasons for AC not working in cars so that you can understand the problems related to AC.

1. Refrigerant Leaking

To run and cool the AC system of a car or other vehicle, refrigerant gas is filled in it, due to which the AC compressor of the vehicle compresses the gas and does the cooling. But sometimes refrigerant leakage occurs in the air conditioner unit of the car.

Due to this, the cooling refrigerant gradually starts leaking, and the AC stops working. In most cases, this can be one of the main reasons for the AC not working in the car. Therefore, you must find the refrigerant leak.

2. Clogged or Leaking AC Evaporator

The evaporator coil is one of the main components for the smooth operation of a vehicle’s air conditioning system. But sometimes, due to not cleaning the cooling coil for a long time or hitting it with something, the cooling coil of the AC gets leaked. Where AC refrigerant leaks, which can be one of the main reasons for a car’s air conditioning system not working.

In many cases, the cooling coil of the air conditioner gets jammed due to a lack of cleaning. Due to this, cooling is not provided by the blower of the air conditioner. So if the cooling coil of the air conditioner system is leaking, you can replace it with a new cooling coil and clean it if the cooling coil is clogged.

Always remember that this work should be done by a professional mechanic only, as there is a high possibility of refrigerant leaking.

3. AC Condenser or Pipes Leaking


The car’s air conditioning system has an AC condenser installed at the front, which is connected to the air conditioner unit through an AC condenser pipe. The AC condenser cools the back pressure created by the compressor.

But sometimes, due to some reason, a small leak occurs in the AC condenser or any pipe, due to which the refrigerant starts leaking. Condenser leakage can also be a reason for the AC not working in the car.

4. Blown Fuse


The most important part of the air conditioning system of any vehicle is the AC compressor, which works on the power of the engine. But when there is no need to run the AC, the magnetic clutch is used to stop the compressor.

After the power supply comes, the compressor flywheel gets stuck to the pulley through a magnet, due to which the AC compressor starts working. 12 V DC current is supplied to make magnets in the AC compressor.

But sometimes the fuse of the AC compressor blows and the magnet in the clutch of the compressor does not get electricity, due to which the AC stops working.

5. Magnetic Coil Failure

brunt ac clutch coil

There is a magnet coil inside the AC compressor, which works on a 12 V DC power supply. When the vehicle’s AC is turned on, the magnet coil of the compressor connects to the clutch pulley of the compressor, and the AC compressor rotates with the engine power through the magneto force.

When the AC compressor stops, the power supply to the compressor magnet coil stops, due to which the magnet coil loses its magnetic power. Due to this, the clutch of the compressor gets separated from the pulley being rotated by the engine, and the AC compressor stops working.

But sometimes the AC compressor magnet coil gets damaged due to various reasons. This can also be one of the main reasons for the AC not working in the car.

6. AC Compressor Failure

car ac compressor

Aluminum pistons are installed in AC compressors. When the AC turns on, the piston applies pressure to the refrigerant, which is an essential process for cooling. But sometimes, oil and refrigerant leak from the compressor due to overheating of the AC compressor or damage to the seal or gasket.

Due to which the pistons of the compressor get damaged due to friction or overheating. Due to this, the AC compressor in the car does not work. Many times the bearing of the AC compressor breaks, due to which the AC compressor gets stuck.

7. Wiring Issues

To run the AC compressor of any vehicle, 12 volt DC current is supplied from the electronics unit there. so that the clutch of the AC compressor works.

But sometimes, due to some reason, the power supply wire gets cut or gets burned. So that the power supply is not available in the AC compressor, and the AC compressor cannot start.

8. Serpentine Belt Break


The car’s AC compressor rotates on a serpentine belt driven by the engine, due to which the piston of the compressor creates high pressure on the refrigerant. But sometimes the serpentine belt becomes loose or breaks due to age.

A loose or broken serpentine belt is unable to rotate the AC compressor, causing the air conditioning system to stop working.

9. Engine Overheating


Whenever the car engine’s normal temperature is ’95 degrees to 98 degrees, But sometimes, due to some reason, the temperature of the engine becomes higher than normal, causing the engine to start overheating. The coolant temperature sensor then sends a high-temperature signal to the ECU.

Thereby, the ECU turns off the power supply to the model AC compressor, and the AC compressor turns off. Therefore, this can also be one of the main reasons for the AC not working in the car. So always keep the temperature of your car normal.

10. Faulty AC Control Panel


Inside any vehicle, the AC control panel is installed on the dashboard in the cabin. From here, the user can manage all the functions of the air conditioner, and through this panel, the power supply of the AC compressor is managed.

But this panel can get old or defective due to some other reason, due to which the functions and power supply of the vehicle’s air conditioner can be disrupted. This can be one of the reasons why the one in the car is not working.

11. Bad Power Relay

Direct power can be provided to make the AC compressor run smoothly. because the AC compressor is controlled by an ECU module, for which power is supplied through a relay.

But many times, the AC compressor relay gets burned and damaged over time. Due to this, the AC compressor of your car may not start in that situation.

How To Fix AC Not Working In The Car?

  • Check The Thermostat – If the AC is not working in the car, check the thermostat. If it is bad, replace it with a new one.
  • Inspect Fuses – Check the fuses related to the AC system. If the fuse is blown, replace it with a new fuse with the proper amperage.
  • Check Refrigerant Level – If the refrigerant level in your vehicle’s AC system is low, this may also cause the AC to not work. So in this case, check the refrigerant level using a pressure gauge. If the level is low, fill in the correct amount of refrigerant.
  • Check The Compressor Clutch – With the engine running and the AC on, check if the compressor clutch is working properly. If not, there may be a problem with the clutch or electromagnetic coil, so get it repaired or replaced properly.
  • Check For Refrigerant Leaks – Oily residue or green stains around AC components can be signs of a refrigerant leak. If this occurs, thoroughly inspect and repair the refrigerant leak.
  • Inspect The Condenser – Clean any dirt or debris from the AC condenser. Many times the condenser breaks, which has to be repaired properly, or a new one has to be installed.
  • Inspect The Cooling Fan – Make sure the radiator and condenser fans are working properly. If they are not working, it may cause inadequate cooling of the refrigerant, causing you to feel hot air even when the AC is running.
  • Check The Cabin Filter – A clogged or dirty cabin air filter can restrict airflow. If the filter is dirty or clogged, replace it with a new one.
  • Check The Blower Motor – If there is no air coming from the vent, the blower motor is bad; Repair it or replace it. However, sometimes the blower motor fuse also blows.
  • Check The AC Control Panel – Check the AC control panel and buttons. If the control buttons are unresponsive, there is a problem with the control unit, Repair it properly or replace it with a new one.


Frequently asked questions related to car AC not working and their answers are given below, which will help in making it more useful for the user.

How To Fix AC in Car Not Blowing Cold Air?

If your car’s AC is not working, then to fix it, you should first check the reason, and after finding the reason, work on fixing it. Because the refrigerant flows at high pressure and without experience, refrigerant leakage problems can occur, which can cause the car AC to stop completely.

How to Recharge Your Car AC?

Activate the air conditioning in your vehicle.
Check to see if the AC compressor is on.
Check the pressure.
Attach the kit’s charging pipe.
restart the car and keep an eye on the gauge.
Connect the recharge hose to the refrigerant can.
Check the temperature inside the vehicle once again.
Your AC has been successfully recharged.

Why is Car AC Blowing Warm Air?

If the car’s AC is running but warm air is coming from it, then the main reason for this is a clogged condenser or a bad condenser fan. Additionally, there may be a dirty or leaking evaporator. In many cases, the AC compressor may also fail.

Share If You Like

Leave a Comment

error: Content is protected !!