Why Is My Car AC Not Blowing Cold Air? (Reasons & How To Fix)

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ac not blowing cold air car

Summertime is fast approaching, and that implies one thing – HOT CARS! If your air conditioning isn’t blowing cold air, you’re going to be an unfortunate driver.  Sweltering heat devastates a vast portion of the world, making the afternoon commute quite unpleasant.

Fortunately, most automobiles today come equipped with air conditioning, which can end to this oppressive heat. However, it’s worth mentioning that these systems are only successful if everything works as planned.

As with any other mechanical system, a car’s air conditioning system is prone to failure due to component damage or malfunction. While significant advancements in the structure quality of numerous AC components have been manufactured over the last decade, problems of countless different types continue to emerge on occasion.

Continue reading to understand more about how your car’s air conditioner works and the most widely known causes of a car AC not blowing cool air. Being stuck in an automobile that’s blowing hot air on a scorching day isn’t something anyone looks forward to.

How A Car AC System Functions

air conditioning system

Before we proceed to the various reasons why your car AC not blowing cold air, let’s have first examine how your car air conditioner actually works. Your car air conditioning system operates by cycling the refrigerant, turning it from gas to liquid, and recycling it.

By the conclusion of this cycle, it has chilled into a cold gaseous condition within its evaporator; during such time, it’s blasted over by external air, chilled, and finally transported to your cabin.

We’ll go through each of the significant components of your car air conditioning system and how they utilize refrigerants to chill the external surrounding air before it enters your car.

High-Pressure Point

AC Compressor

An automobile air conditioner compressor is driven by a pulley connected to your engine’s crankshaft through a belt. This provides power to five to ten pistons. They absorb low-pressure and low-temperature gas before compressing it to produce high-pressure and high-temperature gas.

The compressor clutch determines if the AC compressor obtains power through the crankshaft. This gas is routed to the condenser, the following component of the car air conditioner.


By the stage the refrigerant hits the condenser, it’s scalding due to the pressurization. Its purpose is to absorb this heat and transport it away from the air conditioning system. Consider this component as a radiator’s brother, as they look similar; it radiates heat outwardly when the gas flows through it.

Additionally, air flows through the condenser, cooling the refrigerant while it passes through. This enables it to condense, reverting to its original state as a high-pressure liquid at a lower temperature.


The receiver/dryer is equipped with an input and an output point. The input point receives high-pressure liquid straight from the condenser and screens and desiccants it. If you’re unfamiliar with the term, a desiccant is a material that collects moisture. This is a similar material used to keep shoes and pharmaceuticals dry and fresh.

Filters eliminate contaminants that might be harmful to the AC system, such as dust, grime, and metal fragments, while desiccants absorb moisture.

Low-Pressure Point

Expansion Valve/Orifice Tube

The expansion valve is primarily a regulator for the amount of refrigerant that is permitted to flow thru your car AC system. Not only does this procedure lower pressure, but it also swiftly cools the refrigerant.

An accumulator substitutes a receiver dryer through an ac system with an orifice tube. It operates comparable to the receiver dryer except that it is located between an evaporator and compressor.

The distinction between the orifice tube and the expansion valve would be that the former features a fixed aperture while the latter has a variable aperture. And the latter may vary its aperture in response to the evaporator’s temperature.


An evaporator is similar to a condenser or radiator in that it has channels through which the refrigerant passes. Rather than releasing heat, this process absorbs it, decreasing the temperature to around 32 degrees.

Unlike water, the refrigerant boils at 32 degrees. This reverts it to a gaseous form, which allows it to absorb further heat. This gas is then reintroduced into your compressor to restart the cycle.


Apart from these fundamental components, each AC system incorporates some sensors, providing critical input for optimal system performance. The following explains these sensors and their overall function.

Low-Pressure Switch

Its low-pressure switch is primarily intended to identify a significant loss of refrigerant and the accompanying lubricating fluid.

Whenever the low-pressure point system decreases below a preset amount, its low-pressure switch is triggered, thereby shutting off the system’s compressor and reducing the chance of breakdown.

High-Pressure Switch

The high-pressure switch primarily monitors refrigerant over-pressurization inside the AC system. Whenever system pressures increase for whatever cause, its high-pressure switch gets triggered, preventing the compressor clutch from operating.

Ambient Temperature Sensor

Modern car A/C systems rely on an ambient temperature sensor for providing real-time cabin temperatures. This data is utilized to optimize cooling capacity and maintain consistent cabin temperatures over various operating scenarios.

Reasons Why A Car AC Is Not Blowing Cold Air

The most typical cause for your car’s AC to blow hot air is a faulty compressor or refrigerant leaks. Numerous automobile AC cooling issues involve a fully inoperative AC, hot air blowing from it, or the AC is blowing cold air rather than maintaining adequate cold temps.

With the typical expectation of experiencing cold air when you turn on your AC, the uncertainty occurs when you are instead greeted with blowing warm air. There are various possible reasons why your AC is blowing hot air rather than cool air.

The different causes why your AC is not operating correctly and isn’t blowing cold air consistently. This might be connected to the general repair or servicing required for the several components that make up your car’s cooling system.

Electrical Problems

Any electrical problem resulting in your AC not blowing cool air might be as straightforward as a damaged or blown fuse, relay, fuse socket, or wiring; thus, always begin with that component.

AC issues often need further diagnostics, lengthy disassembly, and specialized equipment, so don’t bother to contact an expert if you’re confused.

Low Refrigerant Level

A low refrigerant level is the most prevalent reason for inadequate AC cooling. Your car’s AC system is a sealed system; a low refrigerant level is frequently the result of an undetected refrigerant leak inside the system. In any case, the source of the leak must be identified and fixed as required before recharging the system.

Excessive Refrigerant Level

Although not as prevalent as low refrigerant, high-pressures due to too much refrigerant might choke an AC process performance. These above-average pressures are frequently the result of system overcharging.

AC System Restrictions

Restrictions within your AC system might also contribute to poor cooling ability. A system restriction smothers refrigerant flow, typically resulting in unintended changes in the system pressures. As a consequence, cooling usually suffers significantly.


A car’s A/C system should be clear of moisture/air contamination for optimal performance. Even a trace of moisture/air might result in unpredictable pressures inside your AC system.

Air is frequently delivered into the system unintentionally when a DIY charging kit is used. Excess moisture could also wreak havoc on the desiccant contained inside the system’s accumulator or receiver/drier.

Faulty Compressor

The compressor that pressurizes the refrigerant in your AC system could perhaps quickly fail when it runs out of oil. Once this happens, adequate cooling is immediately ceased, and the temperature inside the vehicle’s interior begins to increase.

After encountering an internal AC compressor breakdown, it’s also recommended to flush the rest of your cooling system.

Failing Clutch

AC compressors rely on a clutch to operate the remainder of the system’s internal parts. Once all power is removed, the clutch gets magnetically activated and returns to a free-wheel configuration. Whenever an AC clutch breaks, compressor contact becomes difficult.

Bad Cooling Fan Motors

A malfunctioning condenser fan might also harm cooling performance. At most times, your condenser needs sufficient airflow to maintain higher side pressures in control.

A defective cooling fan is usually the culprit whenever your car AC fails to blow cold air while idling yet cools properly while accelerating.

Malfunctioning Sensors

If one of the multiple sensors in your cooling system fails, the system’s functionality will suffer. The car’s computer could have a tough time determining the proper duty cycles of the compressor clutch and will result in your AC not blowing cold air.

Cost To Fix A Car AC

Nobody likes running a car that requires repair work, much more so when the AC is not blowing cool air on a hot summer day. Whenever your vehicle’s AC isn’t working as intended, it’s probably time to take it to a repair. The following is a breakdown of how much you might anticipate repairing a car AC.

  • Assessment and diagnostics – between $80 up to $120 
  • Liquid refrigerant or freon refilling – $80 up to $150
  • Minimal Fixes (Cleanup, Clog Clearing, Leaking refrigerant, Clutch Replacement) – $150 up to $800
  • Complex Repairs/Multiple Problems (Electrical fault, Replace Fan Motors, Blower fan, Compressor, Condenser) – $1,000 or more

Always remember that these prices vary depending on your car’s make and model, the shop/technician, and of course, your location.


Unlike most other systems in modern cars, IF your AC doesn’t have any indicator lights to notify you of potential issues since you don’t like to sit tight until a problem arises, and those troubles all too happen on the most inconvenient occasions.

It’s a great idea to bring your vehicle in before the hot season arrives and ensure that the ducts and fans are in excellent operating order. There are no visible leaks, and your refrigerant or freon levels are adequate. This might potentially be included in your springtime tune-up.

Having your AC inspected before the start of summer, or as early as you spot an issue, could spare you a lot of headache, money, and time. Additionally, it will assist you in staying cool during the summer.


Why is my AC blowing but not cold?

Your refrigerant level could be lower whenever your central AC isn’t delivering cooler air. The device may be running short on refrigerant and will require extra refrigerant. Leakage is the most probable source of this. If you detect a refrigerant loss, you must immediately call a certified mechanic or a qualified HVAC specialist.

Why did my AC stop working all of a sudden?

If your AC stops operating unexpectedly, it might be a sign of trouble, or it could be as straightforward as a blown fuse. It’s essential to keep in mind that frequent issues with ACs could be attributed to insufficient maintenance.

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