Why Is My Car AC Compressor Not Turning Off [Solved]

A well-maintained car AC compressor with the correct level of refrigerant should cycle on and off as needed. It will not run all the time. If there is a low level of refrigerant gas, the compressor will not turn off because it needs to continue the cycle to cool down the cabin. 

Therefore, a dirty air filter, a clogged condenser, and a dirty evaporator coil also cause the compressor to not turn off. 

Once you deal with those problems and don’t take the necessary steps to solve them, the compressor will get fully defective. As a result, you need to spend extra bucks to replace the compressor. 

Continue to read this guide on Car AC Compressor Not Turning Off and reveal the reasons behind this issue. 

car ac compressor not turning off

Table of Contents

Why Is My Car AC Compressor Not Turning Off [Solved]

Your car AC compressor is not turning off due to the automatic climate control, low-level refrigerant, and a clogged air filter. Besides, the car AC compressor will keep running if the evaporator coil or the condenser gets dirty. Below, we will break down each of the culprits. So, continue to scroll. 

Note: You can also read why is my front AC not working but the back is.

1. Automatic Climate Control

Most modern cars now come with automatic climate control features. It automatically controls the climate or temperature of your car’s interior. This automatic climate control system makes the compressor work overtime to cool down the cabin if its switch is in the on position. In other words, your car’s AC compressor won’t turn off if the automatic climate control system’s switch is set to the On position. 

The only way you can stop the compressor from running all the time is to turn off the auto climate control system. 

2. Low Level Of Refrigerant

Low-level refrigerant is another culprit that causes your car’s AC compressor to not turn off. If there is a low level of refrigerant in the compressor, the compressor will cycle more often. 

Indeed, it works hard to continue the cycle and keep the compressor running. If you don’t fill the compressor with fresh refrigerant, it keeps turning on but fails and damages the compressor once it gets dried. 

3. A Clogged Air Filter

For proper AC compressor operation, the air filter of your car’s AC should be free of dirt & debris. If the air filter gets blocked, it will fail to draw sufficient airflow.

And without enough airflow, the system will fail to remove humidity and cool down the air. Consequently, your car’s AC compressor will continue its operation when it shouldn’t. 

To avoid this issue, you should check the air filter of your car’s HVAC system periodically for blockage. 

4. Evaporator Coil Gets Dirty

A dirty evaporator coil can also cause your car’s AC compressor to not turn off. If the evaporator coil gets filthy because of dirt & debris, it will affect the cooling process and make the ac compressor work harder to cool down the cabin. In short, the compressor will keep running all the time. 

5. A Clogged Condenser

Like a dirty evaporator coil, the clogged condenser is also responsible for a malfunctioning car AC compressor. 

If the condenser gets clogged by dirt and debris, it fails to cool down the compressed air and hot refrigerant passes through. Consequently, the ac compressor works harder or overworks to cool down your car interior. 

To bring the car AC compressor back to its normal operating state, you should clean the condenser. If you don’t know how to do the task, hire a professional to clean the condenser

FAQs:

Does an auto AC compressor run all the time?

A functional auto AC compressor will never run all the time unless you keep the auto climate control turned on. Besides, other issues like low-level refrigerant, a filthy condenser, or a dirty evaporator coil are also responsible for this issue. 

How long should the AC clutch stay engaged?

The AC clutch of a functional car AC system should stay engaged for 3 seconds and it will disengage for 3 seconds. It will repeat this cycle to run the cycle to let the HVAC system of your car work properly. If the car AC compressor stays engaged all the time, understand there are issues with the thermostat, air conditioner heater, or the fuse gets broken. 

How to manually engage the AC compressor clutch?

To engage the AC compressor clutch manually, disconnect the single wire connector at the front side of the compressor. Then, take the negative wire of the jumper and connect it to the wire from where you just detached the compressor wire. Next, attach the positive jumper wire to the positive terminal of your car battery. It will help engage the AC compressor clutch manually. 

Conclusion

Your car AC compressor will cycle on and off to cool down the cabin. It will never run all the time unless the AC compressor starts malfunctioning. Fortunately, we mentioned all the culprits that prevent the car AC compressor from turning off. If you want your AC compressor to work normally, just solve those issues. In this case, you can hire a professional if you are not mechanically inclined. 

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