You have just taken your car on the road. Once you accelerate and experience unexpected thing, air conditioner turns off instantly. Likewise, many car owners keep asking, “why does my AC turn of when I accelerate?” Even I used to become frustrated when this happened with my car. So, I have thought of discussing this topic in this article.
Air conditioning keeps us comfortable when we drive our car on hot summer days. But things feel different when it suddenly stops blowing cool air or completely shuts off. The reason is typically the interaction between the car’s AC system and the engine’s power output.
The general function of an AC system is that the engine powers it to work properly. Thus, the engine needs more power to propel the vehicle forward when accelerating. It puts an additional load on the machine that impacts the AC. If the delivered power is insufficient, your AC may turn off during acceleration.
Let us explore more underlying factors of why AC turns off when the driver accelerates. Also, you will learn how to prevent the issue in the rest part.
Understanding the Basics of Automotive Air Conditioning Systems
Before finding the reasons, understanding the basics of AC can be helpful. An AC system consists of several components to cool and dehumidify the car’s internal air by working together.
The AC compressor is one of the significant parts of the system. The engine powers it to pressurize the refrigerant.
After getting enough power, it absorbs internal car heat. Then, the refrigerant flows through the air conditioning system. Simultaneously, it releases heat and transforms back into a liquid. This liquid passes through the AC condenser.
The process does not stop here. The cooled refrigerant liquid then enters the evaporator. However, this evaporator is in the car’s cabin. It absorbs heat from the air and causes the air to cool down. Next, the refrigerant returns to the compressor to repeat the cycle.
This continuous process maintains a comfortable temperature inside the vehicle.
Let us come back to acceleration and AC turning off. During acceleration, the engine requires more power, leading to increased load and strain. This extra load affects the engine’s ability to drive all components, including the compressor. Then, the AC system may temporarily shut off or struggle to operate at its full capacity.
How AC Systems Interact with Engine Power
If you want to know the reasons of AC turns off while accelerating it, understand the interaction between engine power and engine power. I have already explained how the high-power demand of the engine affects the AC system. Let me explain something more.
When accelerating your car, the engine prioritizes power delivery to essential components like the transmission and wheels. As you want to keep AC running at one go, the problem of temporarily reducing the power supply to the compressor appears. This reduction causes a brief shutdown or reduced performance of the AC system.
Acceleration can cause fluctuations in the electrical load on the engine. If the load becomes too high, it can affect the overall AC performance. Besides, electrical issues like faulty wiring, connectors, or sensors can further exacerbate the problem. Then, you get your air conditioner shut off during acceleration.
Common Causes of AC Shutdown During Acceleration (Experts Thoughts)
“Why does my AC turn off when I accelerate?” – this problem can happen due to various reasons. When you understand them, it will be easier for you to solve the problem.
First, I want to add some experts’ opinions regarding the causes of AC turning off during acceleration.
Robert Tomashek, an experienced automotive engineer, explains it in this way:
“Typically, this occurs due to a bad vacuum check valve under the hood. During hard acceleration, the AC door system loses vacuum, causing the doors to default to the windshield. This check valve keeps this from occurring.” (Source: YourMechanic)
Joe Mennei on Quora thread explains:
“If you are noticing this drastic of a power loss, however, you might have a pulley, tensioner or ac compressor failing.”
He accuses the insufficiency of power from the car engine to the AC compressor, which I have already discussed.
Another source claims that the car’s computer is designed to accelerate the vehicle for more speed, AC will automatically shut off. Similarly, a member on Subaru Outback refers to the computer design that turns the AC compressor off under full or near full throttle.
On a thread of CarTalk, a member uniquely explains the matter. He points to the TPS (throttle position sensor) provides the WOT (wide open throttle) signal to the PCM amid acceleration. It cuts off the engine power to the car AC clutch that turns the AC system.
Other Reasons for AC Shutdown During Acceleration
Let us figure out some other reasons for AC shutting down when you accelerate the vehicle:
Electrical Issues
Faulty wiring, loose connections, or malfunctioning electrical components can disrupt the power supply to the AC system. This power supply disruption causes the AC to shut down during acceleration.
Overheating
The engine may be running hot for some reason. They can be malfunctioning cooling systems or low coolant levels. Hence, the air conditioning system is programmed to go offline momentarily to reduce engine load. It may also prevent further overheating.
Compressor Clutch Failure
The compressor clutch engages and disengages the AC compressor. However, a faulty or worn-out clutch may fail to engage properly when the engine load increases during acceleration. Your car AC will shut off at this situation.
Thermal Protection Mechanism
Some vehicles are equipped with a thermal protection mechanism. It safeguards the AC from damage from excessive heat or strain. Likewise, the system may shut off the AC for moments when it detects high temperatures or excessive load.
Insufficient Refrigerant Levels
When the refrigerant levels are low, the AC shuts down during acceleration. It is a great protective measure of the system. Thus, insufficient refrigerant affects the system’s ability to effectively cool the internal car air. It leads to a temporary turn-off.
Sensor Malfunction
Some specific sensors can monitor various parameters of the AC system. A malfunctioning sensor, like the ambient temperature or pressure sensor, can send incorrect signals to the AC system. Then, it triggers shutdowns during acceleration.
Electrical System Fluctuations
Fluctuation is a common issue in the vehicle’s electrical system. These can be voltage spikes or drops that ensure AC performance. When you hit the gas pedal, these fluctuations may appear, and turn off the AC.
Symptoms and Signs of AC Shutdown during Acceleration
Many of us do not like the AC shutdown especially when we accelerate the car. Some notable signs of AC shutdown during acceleration are:
Sudden Loss of Cooling
The sudden cooling loss can be a sign of AC shutdown when you accelerate. You may feel a significant decrease in the airflow when you want to speed up the car. Again, you may notice a noticeable cabin temperature increase when you accelerate.
Brief AC Operation Interruption
The AC system may shut off briefly during acceleration. Then, it may resume regular operation, releasing the accelerator pedal or reaching a steady speed. This erratic behavior can be an indicator of AC shutdowns during acceleration.
Reduced Airflow
You may notice that the air from the vents feels less forceful. Otherwise, you may also experience that AC is not cooling down as effectively during acceleration.
Inconsistent Performance
The AC system may exhibit inconsistent performance. Check if your car AC works well at idle or low speeds. But it is shutting down, providing insufficient cooling upon acceleration, or driving at higher speeds.
Increased Noise or Vibration
You may hear unusual noises or vibrations coming from the AC system. It indicates a mechanical issue with the AC compressor engagement during acceleration.
Dashboard Indicator Lights
Sometimes, the AC shutdown may trigger warning lights on the vehicle’s dashboard. You may look for any AC-related or engine-related warning lights that illuminate during or after acceleration.
Frequently Asked Questions (FAQs)
Why does my AC turn off only during acceleration?
AC shutdown during acceleration typically happens for the increased engine load. It affects the power distribution to the AC system. Therefore, your AC goes off when you accelerate the car.
Can a faulty battery cause AC shutdown when you accelerate?
Yes, it can disrupt the AC system’s power supply, leading to shutdowns during acceleration. You should call a professional to inspect if the battery and electrical components work fine.
How does engine overheating affect the AC system?
Engine overheating can trigger thermal protection mechanism. The temporary shut-off reduces the load on the engine. Also, it prevents further damage due to excessive heat.
Final Words
So, “why does my AC turn off when I accelerate?” – I think you have understood why it happens. Usually, the lack of power from the engine to the car’s AC may turn off the air compressor. You will experience the temporary shutdown of the air conditioner for the scarcity of power.
In this blog, I have included all the possible reasons. If you read the whole book, you will also know some other reasons relevant to the topic.
Thanks for spending your precious time.
