will stuck ac contactor cause blower to run


The Causes and Consequences of a Stuck AC Contactor on the Blower System


The air conditioner is an essential appliance in our homes, providing comfort during scorching summer days. While the system seems complex, it consists of several critical components that work together to deliver cool air. One such component is the AC contactor, which plays a crucial role in the operation of the blower system. In this article, we will explore whether a stuck AC contactor can cause the blower to run continuously, the potential consequences, and how to address this issue effectively.

Understanding the AC Contactor:

The AC contactor serves as a switch, controlling the flow of electricity to the various components of the air conditioning system. When the thermostat signals a demand for cool air, the contactor receives an electrical signal to close the circuit and allow the flow of current. This, in turn, energizes the compressor and the blower motor, resulting in the circulation of chilled air throughout the house.

The Role of the Blower Motor:

The blower motor is responsible for circulating air within the air conditioning system. When the contactor activates the blower motor, it initiates the flow of air through the ducts and vents, effectively cooling the living spaces. However, if the AC contactor becomes stuck or fails to function correctly, it can directly impact the blower motor's operation and result in issues such as the blower running continuously.

Can a Stuck AC Contactor Cause the Blower to Run Continuously?

A stuck AC contactor can indeed cause the blower to run continuously. When the contactor becomes stuck in the closed position, it effectively locks the circuit, allowing uninterrupted flow of electricity to the entire system. In this scenario, the blower motor receives power without interruption, leading to continuous operation even when it is not required. This can result in reduced energy efficiency, increased wear and tear on the blower motor, and uncomfortable indoor temperatures.

Consequences of a Stuck AC Contactor on the Blower System:

1. Increased Energy Consumption:

When the blower motor runs continuously due to a stuck AC contactor, it leads to a spike in energy consumption. Since the blower is in operation even when cooling is not required, it consumes unnecessary electricity, resulting in higher utility bills.

2. Reduced Lifespan of the Blower Motor:

Continuous operation of the blower motor due to a stuck AC contactor places undue stress on the motor's components. Over time, this can lead to premature wear and tear, significantly reducing the motor's lifespan. This can be a costly issue to resolve, requiring replacement or repairs.

3. Uncomfortable Indoor Temperatures:

With the blower motor running continuously, the air conditioner may struggle to maintain desired indoor temperatures efficiently. This can lead to inadequate cooling, resulting in discomfort for the occupants. Additionally, the constant circulation of air can cause fluctuations in humidity levels, further impacting the overall comfort within the living spaces.

4. Increased Risk of Overheating:

Continued operation of the blower motor due to a stuck contactor can strain the system, potentially leading to overheating. Overheating can result in component damage, requiring extensive repairs or replacements.

5. Unnecessary Noise:

When the blower motor operates continuously, it may generate excessive noise levels. This unwanted noise can be disruptive to daily activities and may indicate an underlying issue with the air conditioning system.

Addressing a Stuck AC Contactor:

If you suspect that a stuck AC contactor is causing the blower to run continuously, it is essential to address the problem promptly. Here are some steps to consider:

1. Power Off the System:

Before attempting any repairs or inspections, ensure that the power to the air conditioning system is turned off. This will prevent the risk of electrical shock and damage to the system components.

2. Visual Inspection:

Inspect the AC contactor visually to identify any visible signs of damage or obstruction. Look for melted or burned contact points, loose wires, or debris that might be preventing the contactor from functioning correctly.

3. Clean or Replace the Contactor:

If there is debris or dirt present on the contactor, carefully clean it using a soft brush or compressed air. Ensuring the contact points are clean and free from obstruction can help restore the contactor's functionality. If the contactor appears damaged or worn, it may be necessary to replace the component entirely.

4. Check the Voltage:

Using a multimeter, check the voltage across the contactor to ensure it is receiving the appropriate electrical signal. If the voltage is incorrect, there may be an issue with the thermostat or wiring that needs to be addressed.

5. Seek Professional Assistance:

If you are uncomfortable performing these steps or suspect a more significant issue with your HVAC system, it is recommended to seek the assistance of a qualified HVAC technician. They have the knowledge and experience to diagnose the problem accurately and undertake any necessary repairs or replacements.


A stuck AC contactor can indeed cause the blower to run continuously, resulting in increased energy consumption, reduced lifespan of the blower motor, uncomfortable temperatures, and higher risks of overheating. Therefore, it is essential to address this issue promptly to mitigate further damage and restore optimal functionality to your air conditioning system. Regular maintenance and inspections can help prevent contactor issues and ensure the efficient operation of your HVAC system.


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