The compressor clutch won’t engage without Freon or with a low Freon level. This is because the compressor clutch is protected by a low-pressure switch which cuts power to the compressor if it sees low pressure in the system due to an insufficient amount of refrigerant.
When the switch activates, the air conditioner’s compressor clutch won’t engage. In fact, it is an issue many car owners face often. If you see such an issue, make haste and fix the issue by consulting a professional mechanic.

Will the Compressor Clutch Engage Without Freon?
The compressor clutch will not engage without Freon. To understand how we must understand how the compressor clutch works first.
How An A/C Compressor Clutch Works
The compressor clutch of a vehicle’s air conditioner works to serve as the breaking point for power distribution to the compressor’s internal drive components. When you turn the A/C off, the A/C compressor pulley-free spools.
In that situation, the air conditioner’s driveshaft gets no rotational speed. As a result, the vehicle’s engine is excused from the additional load that would otherwise cause excessive internal compressor wear. When the air conditioner is turned on, power is delivered to the compressor clutch’s magnetic coil.
This allows the coil to create a magnetic field, facilitating clutch engagement. In that position, the air conditioner’s compressor clutch transmits the full rotational force applied by the engine’s serpentine belt to the compressor’s driveshaft.
Compressor Clutch Will Not Engage Without Freon

There is a low-pressure switch in the car’s air conditioning system. This switch is designed such that it cuts the power or ground delivery to the compressor clutch when there is a lack of pressure in the system.
When the level of refrigerant charge is low or the system is without freon, the compressor will not engage. It is one of the main reasons where the lack of compressor activity can be traced back to. The compressor should be fine once you repair and recharge the system.
Can Low Freon Cause Clutch Not to Engage
There is a switch in your vehicle’s air conditioning system that can detect the low pressure in the system. When the system is in low pressure, it will automatically cut off power or ground delivery to the compressor clutch. When the system is low or empty of Freon, the pressure in the system will be low.
As a result, the compressor clutch will not engage because the low-pressure switch will not allow it to. Subsequently, you will not the compressor spinning.
What Causes AC Clutch Not to Engage

AC compressor clutch may not engage due to various reasons. It can be a blown AC clutch fuse or a relay failure. Faulty switches or a low-pressure lockout due to low refrigerant are also some of the common reasons why the AC clutch does not engage.
Even in a scenario where the refrigerant charge is high, the high-pressure switch will cut power or ground delivery to the compressor clutch. A fault in the air conditioner clutch is also a possible cause behind the clutch not engaging. Often, a failure of the control computer leads to the failure of the clutch.
How Do I Force My AC Clutch to Engage
You can manually engage ac air conditioner’s compressor clutch. This can be done by connecting a jumper wire directly to the compressor wire. When you do this, make sure you fill the compressor with oil. Also, the system must have enough refrigerant at that time.
Frequently Asked Questions
Will the AC compressor work without Freon?
The AC compressor will work without Freon, but it is completely unadvisable to do this. Because once the system starts losing refrigerant, it will eventually cause larger damage to the system which will require larger repair needs and lead to a full system failure.
What activates an AC compressor clutch?
The AC compressor clutch relay typically is activated by the low-pressure switch. The evaporator temperature sensor also plays a role here. Normally in a computer-controlled system, the computer grounds the compressor clutch relay.
What happens to AC with no Freon?
If your AC is low to no Freon, it won’t be able to get rid of as much heat per cooling cycle. This means the system will run longer and work harder to cool your home. As a result, there will be a waste of energy, and the electricity bill will increase.
Conclusion
It is not uncommon to come across AC system-related faults which may result in the compressor clutch not engaging. That being said, it is an undesirable situation and you would want it to be fixed if you do not want further damage to the system. The recommended fix in this situation is the replacement of the compressor with an aftermarket one.
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