6 Reasons Why Your Car AC Is Not Working

Car air conditioning system plays a crucial role in keeping us comfortable during both short and long journeys. Whether it’s staying cool in the scorching summer heat or defogging the windscreen in winter, we rely on our car’s AC system more than we often realize.

However, when the AC is not functioning properly, it can make the driving experience uncomfortable for everyone, including the passengers, driver, and even pets or belongings. Fortunately, many common AC problems have simple solutions, ensuring that your comfort and convenience are restored in no time.

Reasons Why Your Air Conditioning Is Not Working

The coolant leak is one of the major reasons for not working air conditioning. However, a faulty cooling fan, a faulty compressor, a broken condenser, or electrical issues may also stop the working of the air conditioning system.

Let’s discuss these reasons in detail.

1) Coolant Leak

A major reason for car air conditioning system not working is coolant leaks, which can occur due to deteriorating rubber hoses and seals with time. These leaks result in the loss of refrigerant, such as Freon, and not only deprive you of cool air but also pose a risk.

Moisture can enter the system through these leaks and mix with the coolant, forming a corrosive and damaging acidic combination. It’s essential to address refrigerant leaks promptly to prevent further problems and potential permanent damage to the AC system.

2) Damaged Cooling Fan

A damaged cooling fan is one of the major causes of car AC not working. Similar to how blowers push air through home vents, cooling fans in your cars are responsible for circulating refrigerated air into the passenger cabin.

If there is an issue with the cooling fan, the air will not come out of the vents. Cooling fan issues can stem from electrical shorts, blown fuses, or damage caused by contaminants on the road.

Luckily, resolving this problem is usually straightforward, as a mechanic can quickly replace the faulty fan and have your AC system working properly again.

Read More: Bad Cooling Fan Symptoms and Causes

3) Faulty Compressor

The proper functioning of your car’s AC system relies on a functioning compressor that keeps the refrigerant circulating. However, if the compressor is not working correctly, the refrigerant cannot move effectively.

One of the major causes of a faulty compressor is prolonged periods of inactivity, as it may not be used during the cooler seasons of fall and winter when air conditioning is not needed.

Another issue that can affect the compressor is a stuck clutch. If the clutch remains engaged (“on”) continuously, it can cause the AC system to run constantly. Conversely, if the clutch remains disengaged (“off”), the compressor will not activate at all. In either case, it is recommended to have a mechanic inspect the compressor to identify and address the underlying issues.

By having your mechanic diagnose and resolve compressor-related issues, you can restore the proper functioning of your car’s air conditioning system.

4) Broken Condenser

A clogged or broken condenser is one of the major reasons for air conditioning not working.

If there are no visible obstructions in the condenser, there are chances that the condenser itself may be damaged. This can occur due to punctures caused by road dirt that penetrate through the car’s grill and damage the condenser.

Equipment failure can also contribute to a broken condenser. In such cases, replacement is typically the only solution to resolve the issue. 

5) Electrical Issues

Electrical problems can also affect the car’s air conditioning system. Failed switches, blown fuses, problems with the control module, or other issues can disrupt the functioning of the AC.  

Fuse failures or loose connections can lead to electrical shorts, which are relatively easy to fix. However, it is important to address electrical problems promptly as they can cause acid buildup. Acid buildup can result in severe damage to the vehicle and may even necessitate the replacement of the entire air conditioning system.

By promptly addressing electrical issues, you can prevent further damage and ensure the proper functioning of the AC system.

6) Faulty Blower Motor

A bad blower motor may also stop your car’s air conditioning system from working. This motor is responsible for circulating the cooled air into the car’s cabin.

When the blower motor fails, it may result in a lack of airflow, even if the air conditioning system itself is working.

How To Fix Your Car’s AC Problems

If your car’s air conditioning system is not working, follow the below-given steps to fix the issue:

1) Is Your AC On but Not Cooling?

If you find that the AC in your car is set to maximum cool with the fans on high, but it is only blowing reasonably low cold air, there are several steps you can take to troubleshoot the issue:

• Inspect your cooling fan: Make sure that the cooling fan on the radiator or condenser is running when the AC is turned on. If the fans are not functioning properly, it can hinder the airflow and cooling efficiency.
• Look for contaminants: Look for any obstructions such as dirt, bugs, or leaves that could be blocking the airflow over the condenser and clean them if necessary.
• Inspect the cabin air filter: Properly inspect the cabin air filter for damage or corrosion. A dirty or clogged filter may restrict the airflow and affect the cooling performance. If the filter is dirty, replace it with a new one.
• Check the system pressures: Use a manifold gauge set to check the air conditioning system’s pressure. Check your car’s repair manual or online resources for the suggested low-side and high-side pressure values. By observing the pressure readings, you can get an indication of whether the refrigerant level is adequate in the system.

2) Examine the Compressor

Start diagnosing the issue by inspecting the compressor. With the engine running, turn the AC on to maximum cool, set the fans to high, and check if the clutch on the compressor is engaging.

If the clutch is engaging and disengaging in short intervals (every few seconds), it is often a sign of low refrigerant. You may notice a rapid drop in the low-side pressure when the clutch engages, followed by a rise in pressure when it disengages.

Adding more refrigerant can help stabilize the pressure and ensure proper compressor operation.

3) Check For Leaks

The most common issue associated with car air conditioning systems is leaks. If the system’s pressure is insufficient, it often indicates a leak. Here are some steps you can take to detect and locate a leak:

• Use a UV A/C leak detection kit: This is the simplest method to identify leaks. Follow the steps written on the packaging to put UV dye into the system. Then, use a UV light to locate the leaks by looking for fluorescent traces of dye.
• Verify fittings: Properly inspect all the fittings in the system to ensure they are securely tightened. Loose fittings can cause refrigerant to leak.
• Inspect hose manifolds: Examine the hose manifolds connected to the compressor. Look for signs of leaks, such as oil residue or refrigerant stains around the connections.
• Check seals and o-rings: Inspect the front seal and o-rings that seal the pressure switches on the back of some compressors. Damaged or deteriorated seals can result in leaks.
• Examine crimped hoses: Check where the hoses are crimped onto the fittings. Inspect for any signs of leakage or damage in those areas.
• Inspect Schrader Valves: These valves, commonly found on the service ports, can develop leaks. Use a soapy water solution and apply it to the valves while the system is pressurized. If you see bubbles forming, it indicates a leak.
• Look for condenser damage: Inspect the condenser for any pinholes or physical damage that could cause the refrigerant to leak. Be thorough in your inspection.

FAQ Section

What is the function of the car air conditioning?

The main function of a car’s air conditioning system is to provide comfort and maintain a desired temperature inside the vehicle’s cabin. The air conditioning system cools the air inside the cabin by removing heat and reducing the temperature.

Why is AC not working in the car, blowing hot air?

Low refrigerant levels are often the main cause of air conditioning blowing hot air. Refrigerant is a vital liquid that flows throughout the vehicle’s AC system, playing a crucial role in removing heat and humidity from the cabin by expanding and contracting. Without the proper amount of refrigerant, other components of the air conditioning system will not work properly.

How do I fix my AC blowing hot air?

1. Change the faulty air filters
2. Properly check the thermostat settings
3. Defrost evaporator coils
4. Repair the refrigerant leaks 
5. Replace the damaged condenser
6. Replace the faulty blower
7. Replace the faulty compressor

Does coolant affect the air conditioning system?

Yes, coolant can indeed impact the performance of the air conditioning system in several ways. The coolant used in the engine cooling system can have effects on the airflow, humidity, and temperature of the car’s air conditioning system. The proximity of the car’s interior to the engine can influence the temperature of the air coming out of the AC vents.

How do I know if my car AC needs gas?

When it comes to identifying the need for recharging or regassing the air conditioning system, the first signal is usually a decrease in the coolness of the air blown from the vents. If the air feels no different when the A/C is turned off, it could indicate the need for a recharge. If you cannot recall the last time the system was regassed, it is generally recommended to have it done to ensure optimal performance.

Can I use water instead of coolant?

Yes, it is possible to use plain water in a cooling system instead of coolant, but it is not suggested as a long-term solution, especially in severe weather situations. Water alone does not possess the same properties as a proper coolant, such as antifreeze or coolant mixtures, which are specifically designed to regulate temperature and prevent freezing or boiling under varying conditions.

Is the car AC compressor repairable?

When it comes to AC compressors, in some cases, they can be repaired. But it is generally more advisable to replace a faulty compressor with a new one. Replacing the compressor is typically a more efficient and effective solution. It not only saves time but also tends to result in a more durable and reliable repair, ensuring optimal functioning of the AC system.

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