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.
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 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 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 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 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, 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.
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.
The proof image shows the location where the technician tested the blower motor. The technician could diagnose the issue 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.
Car AC not blowing cold air. Air conditioners. AC evaporator. Evaporator drains condensation. AC condenser.