- Why AutoTechIQ
- Fixes
- Shops Near You
- Vehicle Symptoms
- What Are Common Car Failure Searches?
- What Do My Dashboard Warning Lights Mean?
- Why Does My Car Drive Weird?
- Why Does My Car Make Noises?
- Why Does my Car smell?
- Symptoms Without Summary
- Car Leaking Coolant
- AC Isn't Cooling
- AC Blowing Hot Air
- Shaking While Driving
- Overheating AC
- AC Smells Like Vinegar
- Heater Not Working
- Windshield Wipers Don't Work
- Car Leaking Water
- Car Leaking Red Fluid
- Car Battery Leaking
- AC Only Work Sometimes
- Shaking While Idle
- Shaking At High Speeds
- Evap System Leak
- Shaking While Braking At High Speeds
- Shaking When Stopped
- Shaking When Accelerating
- Radiator Leaking
- Pink Fluid Leaking
- Car Leaking Oil
- AC Not Working.
- Car Leaking Gas
- Power Steering Fluid Leak
- Bad Brake Caliper
Hey, Why Is My Car's AC Not Blowing Cold Air?
If you are short on time and want to fast-track the process to professional help, click Yes
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.
Let's Get To The Bottom Of It!
- The blower motor is a part of your car's air conditioning system that helps control th...read more
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.
- The blower motor is responsible for pushing the air from the outside into your car's air conditio...read more
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."
- The expansion valve is a device that helps regulate the flow of a substance called "freon" in an ...read more
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.
- Some cars have computers that modernize their performance. For example, the computer can turn off...read more
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.
- In an air conditioning system, an orifice tube helps turn a liquid substance called freon into a ...read more
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.
- The cabin air filter filters out dust, pollen, and molds from the air that comes out of the vents...read more
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.
Find Professional Help
Please select your vehicle's brand and location so we can locate the best professional help for youVehicle Health Inspection Proof
Explore the following typical inspection results that show a potential cause for the symptom and select the one you believe is similar to your vehicle's issue.
Faulty fan resistor
Expansion valve malfunction
Clogged orifice tube
Clogged air filter
Engine overheating
Blower motor malfunction
The proof image shows the blower motor resistor still in the airbox with the electrical connection connected. This was done to verify that the command voltage was present.
A customer dropped off their vehicle reporting that the fan control's medium speed had not been functioning for about two months. The low speed also stopped working recently, leaving only the high speed.
During a test drive, the technician confirmed that the blower motor only worked at high speed. Despite conducting a vehicle health inspection, the technician found nothing about the customer's concern. However, the customer authorized additional tests.
To begin diagnostics, the technician accessed the blower motor and resistor module. Then, using a digital voltmeter, they tested the command voltage from the control head to the resistor module and verified that the voltage was present at the connector for each speed.
Unfortunately, the power only went to the blower motor when it was set to high speed. This is because if a resistor fails, it can no longer regulate the amount of power supplied to the blower motor, which means that the motor only receives power at one speed (in this case, high speed since it's the only unregulated).
Therefore, the resistor module needs replacement.
1/6
The proof image shows the exposed failing expansion valve buried behind the dash.
A customer dropped off their vehicle concerned about their air conditioning system leaking. They noticed the air conditioning would work fine but suddenly get extremely cold and warm up again. The issue happened regardless of whether the vehicle was stationary or moving.
During a test drive, the technician confirmed that the air vents' temperature fluctuated. Despite conducting a vehicle health inspection, the technician found nothing about the customer's concern. Therefore, the customer authorized additional tests with an AC machine.
An AC machine is a piece of equipment used by automotive technicians to diagnose and service air conditioning systems in vehicles. It is designed to recharge the refrigerant in the AC system, recover refrigerant, and evacuate air from the system.
The technician attached the AC machine to the system, put a temperature gauge in the air vent, and ran the vehicle with the air conditioner on high in the service bay. The ambient air temperature was 98°. The temperature coming out of the center vent dropped down to 58°. As the system continued to operate, the temperature increased to 80°, and the AC would blow warm air.
During this event, the pressure on the "high" side decreased, and the pressure on the "low" side increased, indicating that the expansion valve created the temperature difference unnecessarily.
Based on the diagnostics, the expansion valve needs replacement. The expansion valve is responsible for regulating the flow of refrigerant through the air conditioning system. If the valve fails, it can cause the temperature to fluctuate, as happened in this case.
2/6
The proof image shows the orifice tube clogged with particles from a broken desiccant bag.
A customer dropped off their vehicle concerned about the air conditioner. The customer explained that while the air conditioner initially started very cold, the temperature soon increased, and it felt like warm air was coming out of the vents.
During the test drive, the technician confirmed the customer's observations. After running for about a minute, the high side pressure got extra high, causing the air conditioning system to shut off. Then, the compressor would kick in for 10 seconds before the high-pressure cutout shut it off again.
The technician performed a vehicle health inspection but did not notice anything about the customer's initial concerns. Therefore, the customer authorized additional tests.
An AC machine is a piece of equipment used by automotive technicians to diagnose and service air conditioning systems in vehicles. It is designed to recharge the refrigerant in the AC system, recover refrigerant, and evacuate air from the system.
The technician then hooked up the AC machine to start the air conditioning and discovered that the orifice tube was clogged with broken particles from the accumulator. The hoses had to be taken apart and flushed to resolve the issue. The evaporator also had to be washed with a flushing solvent.
Unfortunately, the condenser and compressor could not be flushed out, so they needed to be replaced with the accumulator and orifice tube. After the replacement, the system would have to be evacuated and recharged.
3/6
The proof image shows the clogged air filter preventing cool air from circulating and stressing the blower motor.
A customer dropped off their vehicle concerned that its AC sounded like it was making extreme efforts. However, although the AC was loud, it wasn't blowing air. They mentioned it worked fine at "medium," but now it doesn't cool even if set on "high."
During a test drive, the technician noticed that the AC's blower motor was noisy. They also saw a lack of air coming from the AC vents. Then, during a vehicle health inspection, they checked the cabin air filter and found it completely clogged.
The technician recommended replacing the air filter and re-testing the AC system.
4/6
The proof image showed the melted fuse and wire in the power center, which supplied power to the cooling fan motor.
A customer towed their vehicle into the shop, reporting the air conditioner wasn't working. Also, the engine temperature light came on, and the engine started overheating after the air conditioner stopped functioning. The customer safely pulled over and turned off the vehicle.
Due to the customer's concerns, the technician did not test-drive the vehicle. Instead, the technician pushed it straight into the service bay. While doing so, they noted that the check engine light was on.
During the vehicle's health inspection, the technician found nothing about the customer's initial concern. The technician then performed a vehicle code scan and discovered an engine overheating condition (p0217 code). As a result, the customer authorized additional tests.
The technician used a vehicle-specific scanner to clear the codes and a scanner's bi-directional controls to activate the cooling fans. These tools revealed that the fans were not turning on when they should have been.
Next, the technician used a digital voltmeter to check if power was getting to the cooling fans. However, they found no voltage at the cooling fan connector. Upon further inspection, the technician discovered that a fuse in the battery's power center was melted, and the wire going to the cooling fan motor was burned. This resulted in the engine running hot.
The technician bypassed the power center to check if the fan would operate, and it did. Finally, the technician concluded that the battery's power center needed to be replaced, which can also happen in modern cars. The voltage regulator might also need to be replaced.
5/6
The proof image shows the location where the technician tested the blower motor. The technician could diagnose an ac system problem with this information and recommend the necessary repairs.
A 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.
6/6Typical Fixes to Address the Cause(s)
The following chapters bases themselves on experiences from our auto repair shop; we'll describe related problems' causes and fixes.
The AutoTechIQ ranking for Safety, Cost Avoidance, and Environmental Impact is
Vehicle Symptoms
Below are just a few examples of typical Symptoms and Fixes your car might be experiencing
Other things your auto repair shop might talk about:
Car AC not blowing cold air. Air conditioners. AC evaporator. Evaporator drains condensation. AC condenser. car ac isnt cold. ac compressor. low refrigerant. warm summer months. locate leaks.