Should Radiator Fan Turn On When Ac Is On?
The radiator fan is a crucial component of the engine cooling system in a vehicle. It helps to regulate the temperature of the engine by blowing air over the radiator and dissipating heat.
The radiator fan also plays an important role when the air conditioning (AC) system is in use, as the AC puts additional strain on the engine and increases the need for cooling. Understanding how the radiator fan works and when it should turn on when the AC is on is essential for maintaining the proper functioning of a vehicle.
In this blog, we will explore the role of the radiator fan in the engine cooling system, how it is controlled, and the ideal conditions for it to turn on when the AC is on. We will also discuss common symptoms of a faulty radiator fan and answer some frequently asked questions.

Should Radiator Fan Turn on When Ac is on?
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How the Radiator Fan Works
The radiator fan is an essential component in the engine cooling system of a vehicle. Its primary function is to regulate the temperature of the engine by blowing air through the radiator to dissipate heat.
The radiator fan operates by drawing air through the radiator, which cools down the coolant that flows through the engine. This coolant helps to regulate the temperature of the engine, preventing it from overheating and causing damage.
The radiator fan is typically controlled by a temperature sensor, which signals the fan to turn on when the engine temperature reaches a certain level. The fan speed may also be regulated based on the speed of the vehicle, the load on the engine, and other factors.
There are a variety of factors that can affect the radiator fan’s operation, including the age and condition of the fan itself, the temperature of the coolant, and the amount of air flow through the radiator.
If the fan is not functioning properly, it can lead to engine overheating, decreased fuel efficiency, and other issues. It is important to regularly check the operation of the radiator fan and address any problems that arise to ensure optimal engine performance.
When the Radiator Fan Should Turn on When the Ac is on
The radiator fan plays an important role in the engine cooling system, and it’s operation is affected by the air conditioning system as well. The air conditioning system increases the pressure in the engine, and as a result, the radiator fan needs to work harder to dissipate the heat generated by the engine.
The pressure switch is responsible for controlling the radiator fan, and it is activated when the pressure in the engine reaches a certain level. The ideal pressure range for the radiator fan to turn on when the AC is on is between 13 and 15 PSI.
When the pressure exceeds this range, the pressure switch activates the radiator fan, which then helps to lower the pressure and keep the engine running at a safe temperature.
The radiator fan is an essential component of the engine cooling system, and it is important to ensure that it is functioning correctly, especially when the air conditioning system is in use. If the radiator fan fails to turn on when the AC is on, it can lead to overheating and engine damage, which can be costly to repair.
Symptoms of a Faulty Radiator Fan
The radiator fan plays a crucial role in maintaining the engine’s temperature, and when it is not working correctly, it can result in several noticeable symptoms. One of the most obvious signs of a faulty radiator fan is engine overheating.
The radiator fan helps to dissipate heat from the engine, and without it, the engine temperature can quickly rise to dangerous levels. This can lead to permanent damage to the engine components and a decrease in the vehicle’s overall performance.
Another symptom of a faulty radiator fan is poor air conditioning performance. The radiator fan is responsible for blowing air through the AC condenser, which helps to cool the refrigerant. If the fan is not working, the AC system will struggle to cool the cabin effectively.
Finally, an engine warning light may illuminate, indicating that there is a problem with the radiator fan or other components of the cooling system. If the radiator fan is not functioning properly, it is essential to address the issue as soon as possible to prevent further damage to the engine and the vehicle’s performance.
Common Symptoms of a Faulty Radiator Fan
Symptom | Explanation |
---|---|
Engine Overheating | The radiator fan’s primary function is to cool the engine by removing heat from the radiator. When the fan is not functioning properly, the engine can overheat, causing damage to the engine components. |
Poor AC Performance | The radiator fan also helps to cool the AC condenser, which is responsible for removing heat from the refrigerant. If the fan is not working correctly, the AC performance will decrease, and the AC may not cool the vehicle effectively. |
Engine Warning Light | The engine management system is responsible for monitoring the operation of the radiator fan. If the fan is not functioning correctly, the engine warning light may come on, indicating a problem with the cooling system. |
FAQs
If the radiator fan fails to turn on, the engine can overheat, which can cause serious damage to the engine. It can also result in poor air conditioning performance, as the fan is needed to dissipate heat generated by the AC system.
It is not recommended to drive your car if the radiator fan is not working, as it can cause engine overheating and damage. If you have to drive, keep the speed low and avoid heavy loads.
There are many potential causes of a radiator fan failure, including a blown fuse, a broken fan motor, a faulty relay, or a malfunctioning pressure switch.
You can check if your radiator fan is working by observing the fan blades while the engine is running. If the blades are turning, the fan is working. You can also use a diagnostic tool to check the fan’s operation.
Replacing a radiator fan can be a complicated job that requires mechanical expertise. If you are not confident in your abilities, it is best to have a professional perform the replacement.
Conclusion
The radiator fan plays a critical role in the engine cooling system by removing heat from the coolant and blowing it through the radiator. The fan is usually controlled by the pressure switch and turns on when the AC is on to regulate the pressure in the system.
A faulty radiator fan can cause engine overheating, poor AC performance, and an engine warning light. Regular maintenance and prompt attention to any signs of a malfunctioning radiator fan can help prevent more serious engine problems and ensure safe and reliable operation of your vehicle.