Four common causes for an AC not cooling the vehicle and their related parts.

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Is Your Car's AC Not Blowing Cold Air?

The AC isn’t blowing cold air because the cabin air filter is clogged, the blower motor is faulty, or there’s an issue with the fan’s resistor. However, less commonly, it might also be that the engine is overheating or has a faulty refrigerant flow. It can also be a malfunction in the expansion valve, electrical control, a clogged orifice tube, or related issues.

Consider having an experienced professional diagnose and discuss the problem promptly. Doing so ensures that your vehicle remains in good working order and you're safe while driving. Don't let a minor issue become a significant problem that could have been avoided with prompt attention and maintenance.

Watch out: If your car's air conditioning system is not cooling, you must immediately take action. Ignoring this issue may cause your hot summer months to become tougher.

The most common causes for a vehicle’s windshield wipers not working

The most common causes for the car’s windshield wipers not working:

Faulty fan resistor: A resistor is an electrical component that manages the power sent toward the condenser fin, making it work at the proper voltage. If the resistor is faulty due to electrical problems, the condenser fan, which is essential to keep airflow and low temperatures inside the air conditioner, stops working. Consequently, the AC malfunctions.
Expansion valve malfunction: The expansion valve manages the refrigerant amount flowing into the evaporator core. However, this valve can fail due to wear, tear, or even freeze up, leading to AC issues and low coolant circulation.
Clogged orifice tube: The orifice tube is a tube that sends refrigerant into the AC evaporator, a component inside the AC system. It works by pressurizing and pushing refrigerant so the AC can use it to cool down the air. However, if the orifice tube fails, refrigerant might stop circulating properly, resulting in AC issues.
Clogged air filter: The cabin air filter is a fabric screen inside the dashboard that catches debris and particles from the air flowing inside the AC system. It's safe to say that the cabin air filter needs regular change since it can accumulate too much residue and become quite dirty.
Engine overheating: An overheating engine can result in too-hot coolant and vapor circulating your vehicle, which eventually affects the AC. If the engine is overheating, the air conditioner has to stress and compensate to bring temperatures lower.
Blower motor malfunction: The blower motor is an electrical device that blows the air from inside the AC system to outside, so it can travel through the vents and get inside the cabin. However, if the blower motor is faulty due to bad connectors or wirings, it won't blow, resulting in bad airflow and a malfunctioning air conditioner.

Frequently Asked Questions

Is the vent not blowing air even if set on high?

The blower motor is responsible for pushing the air from the outside into your car's air conditioning system. This air goes through a filter and then through a part called the evaporator core, which helps cool the air. The blower motor has different speed settings that you can control to adjust the airflow in your car. However, the blower motor can wear out over time and stop working correctly. If this happens, no air will come out of the vents in your car, even if you set the speed settings to "high."
Is the air coming from the AC changing temperature constantly?

The expansion valve is a device that helps regulate the flow of a substance called "freon" in an air conditioning system. The valve works by reducing the pressure of the freon. This causes the freon to change from a liquid to a gas, which helps it absorb heat and make the air colder.

However, the part of the valve that controls how much freon flows through can wear out or break. This can cause the valve to malfunction and make the air coming out of the air conditioner shift temperature quickly, constantly feeling warmer and cooler.
Did the temperature light come on the dash after the AC quit blowing cold air?

Some cars have computers that modernize their performance. For example, the computer can turn off car parts that might make the engine overheat. So, if the air conditioner is on and the engine is overheating, the computer turns off the air conditioner before the heat gets extreme. This safety behavior prevents the engine from overheating and causing damage. But it does make the temperature light flash on the dashboard.
Does the air from the vent start cold and then get really hot?

In an air conditioning system, an orifice tube helps turn a liquid substance called freon into a gas. This part helps the system absorb heat and cool the air. The tube has a screen to keep external particles out, but if something significant goes wrong inside the air conditioning system, like a part breaking, those particles can get through and block the orifice. This can cause the air conditioning system to stop working correctly and even shut down to protect itself. Hence, the air might start cold and then heat over time.
Does the AC sound like it's going overboard but struggling to blow air out?

The cabin air filter filters out dust, pollen, and molds from the air that comes out of the vents, ensuring that it is safe for the occupants to breathe. However, the filter can clog up if you don't change it regularly. If this happens, air struggles to flow through the filter and into your car's vents. Consequently, your air conditioner works less effectively, and the blower motor overstresses, making louder efforts.
Is the AC only venting when set at high?

The blower motor is a part of your car's air conditioning system that helps control the fan's speed. It does this by using particular features called resistors to reduce the amount of power going to the fan, slowing it down. However, if the resistors go wrong, they can stop working and prevent the fan from running at certain speeds. If the resistor fails, there won't be resistance, so the fan will only work at the highest speed setting, which means you won't be able to adjust the fan speed as you normally would.

Typical fixes to address the cause(s)

These are typical processes and repair services that fix a check engine light issue

The most common cause: Faulty blower motor

The most common reason for a car’s AC to stop working is due to a faulty blower motor. The blower motor can stop working due to connectivity and wiring issues. Your vehicle's heating and cooling systems need the blower motor to blow warm air through the HVAC (heating, ventilation, and air conditioning) vents. However, if the blower motor doesn't work, your vehicle's air vents won't blow any air.

Symptoms it causes: Apart from the AC not working you might notice heater issues, humming noises, a burning plastic smell, etc.
Medium risk of priority: Wiring problems with the blower motor can result in warm air accumulating inside the system, and overheating other components. Additionally, a faulty blower motor might overstress other components like the blend door, leading to heftier repairs.

How exactly does the blower motor wiring fail?

The blower motor relies on wirings and connectors since it needs power to work. However, electrical problems can pop up leading to short-circuit and overstress, resulting in wiring issues. Additionally, driving conditions can also strain the blower motor wiring due to friction and vibration from rough driving.

Go safe: Ask for a mechanic to inspect your vehicle’s HVAC system to investigate if the blower motor is faulty due to surrounding components and if there’s further damage to check out. Many shops do transparent vehicle inspections and lay out your options after investigating your vehicle’s conditions.

What’s a vehicle inspection? It’s “detective work” on your vehicle, checking its systems to see if anything prevents the car from working as expected. In this case, mechanics examine different parts of your vehicle to track if anything is causing the blower motor wiring to wear out. They’ll also check the condition of components during their inspection, noting which are causing the problem and which got affected by it, recommending to replace them in order of priority.

Transparency example in a faulty wiper motor service

An HVAC system inspection is the most transparent process to understand why your vehicle’s air filter is faulty. This is because many components surrounding the air filter, blower motor, and blend door can have a say in the issue, indicating the real culprits that caused it all.

Let’s read an example of how this kind of inspection helps to service a faulty blower motor.

A customer dropped off their vehicle concerned that the air conditioner was malfunctioning. They reported that the AC light on the control knob was turning on, but no cool air was coming out of the vents. Additionally, they mentioned that the blower motor had been getting loud before the air conditioner stopped working.

During a test drive, the technician confirmed that the blower motor was not functioning. However, during a vehicle health inspection, they did not notice anything about the customer's concern. As a result, the customer authorized additional procedures.

To investigate further, the technician accessed the blower motor connector and unplugged it to inspect for damage. Although the connector appeared in good condition, the technician reattached it and used a digital voltmeter to confirm that power and ground were getting to the blower motor. However, the blower motor still did not turn on.

After tapping on the bottom of the blower motor housing, the technician got it to turn on, although it was making a lot of noise. Finally, the technician determined that the blower motor was failing and needed to be replaced.

Blower motor malfunction

In this case, the mechanic put the “Immediate Action” tag on the blower motor, connectors, and wiring.

Similar Symptoms

Below are just a few examples of typical Symptoms and Fixes your car might be experiencing

Four common causes for a vehicle AC not working and their related parts.

Is Your Car's AC Not Blowing Cold Air?

The most common causes for a vehicle’s windshield wipers not working

Frequently Asked Questions

Is the vent not blowing air even if set on high?

Is the air coming from the AC changing temperature constantly?

Did the temperature light come on the dash after the AC quit blowing cold air?

Does the air from the vent start cold and then get really hot?

Does the AC sound like it's going overboard but struggling to blow air out?

Is the AC only venting when set at high?

Typical fixes to address the cause(s)

The most common cause: Faulty blower motor

How exactly does the blower motor wiring fail?

Transparency example in a faulty wiper motor service

Similar Symptoms

Why Is My Car's AC Not Working?

Why Is My Car's AC Blowing Hot Air?

Why Is My Car Overheating When I Turn The AC On?

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