The clutch of an A/C compressor transfers all of the rotational force generated by an engine’s serpentine belt to the compressor’s driveshaft when it is in the “on” or “engaged” state.
However, the associated clutch coil is de-energized when the vehicle’s A/C system is turned off. The A/C system clutch then disengages. If the refrigerant in an air conditioning system is low, a clutch may engage and disengage alternatively.
When an AC compressor clutch engages, a vehicle may occasionally run poorly, which is usually caused by the additional load the pump places on the engine.
Well, in this reading, we’ll explore what an AC compressor clutch is, its functions, its location, and how it works. We’ll also look at its symptoms, causes, and replacement cost of a bad one.
Let’s begin!
What is AC Compressor Clutch?
The AC compressor clutch is a device that connects and disconnects the AC compressor from the engine. The air conditioning system’s compressor is responsible for compressing and circulating the refrigerant.
When the air conditioning system is turned on, the compressor clutch engages, and when the system is turned off, it disengages. The AC compressor clutch relay and the AC compressor clutch cycling pressure switch are used to control the compressor clutch.
When the air conditioning system is turned on, the relay sends power to the compressor clutch, and the cycling pressure switch monitors the refrigerant pressure and sends a signal to the relay to turn off the compressor if the pressure rises too high.
One of the most vital parts of a car’s air conditioning system is the compressor clutch. This mechanical component pushes the cooled air through the system and pressurizes the entire A/C system to make sure everything functions properly.
But because it goes on and off frequently, it begins to deteriorate and break.
Your air conditioner won’t blow cool air for very long if the compressor clutch is damaged. The flow of refrigerant in the A/C system cannot be properly controlled by a damaged, malfunctioning, or worn compressor to provide the appropriate levels of cooling.
A compressor clutch will often stop engaging when it breaks. Although compressor clutches can be replaced independently from the rest of the compressor, this is generally not advised due to the possibility that other parts will break down.
A clutch may alternately engage and disengage if the refrigerant in an air conditioning system is low. If the cost of genuinely fixing the system is too high, this situation can typically be fixed by simply disconnecting the wire that leads to the clutch.
Related: What is AC Compressor? its Location and How it Works
Function
Energy from the engine is transformed by the AC compressor clutch and sent to the compressor. The clutch engages and starts spinning to transfer power when the air conditioner is turned on.
Additionally, the compressor clutch prevents the air conditioner from running nonstop. You would experience a drop in fuel economy and more frequently worn-out air conditioning parts if it operated continuously. The engine would be put under too much stress as a result.
The air conditioner compressor clutch is a part of the vehicle’s air conditioning system and is meant to engage and disengage the compressor pulley from the compressor drive. A magnetic switch is typically used to control it.
The clutch is powered after the AC is turned on. This causes the compressor drive’s armature plate and compressor belt to engage, causing the compressor drive to rotate alongside the vehicle’s engine.
A friction plate and an electromagnetic coil make up the clutch. When the clutch is engaged, current flows through the coil, producing an electromagnetic force.
The pump rotor receives power from this force, which pulls the coil in the direction of the friction plate and keeps the compressor operating.
The clutch loses electrical power if the AC is turned off. Without this power, the compressor belt and armature plate disengage, which makes the clutch inactive.
Diagram
Where is the AC Compressor Clutch Located?
The AC compressor clutch is generally located at the front of the AC compressor. The AC compressor is typically connected to the engine by a belt and is located at the front of the engine, near the bottom of the engine compartment.
The compressor clutch is a small, circular device positioned on the front of the compressor that is normally about the size of a silver dollar. When the compressor belt is taken off, the front of the compressor can be seen, where a single bolt or snap ring typically holds it in place.
The clutch engages and starts spinning when the air conditioner is turned on. However, depending on the make and model of the vehicle, the exact location of the compressor clutch may vary.
It is advised that you refer to the vehicle’s service manual for detailed instructions on where to find the compressor clutch on your particular vehicle.
Reason Why an AC Compressor Clutch Fail?
There can be a variety of reasons at play when a car’s AC isn’t functioning properly. However, it’s critical to consider the chance that your AC compressor clutch may be faulty.
The compressor has a lot of moving parts, making it challenging to pinpoint which one is damaged, but it is possible to narrow it down to the clutch. However, here are some of the things that can cause your air conditioning compressor clutch to fail:
- When the refrigerant charge is low
- Electrical problems
- Too much refrigerant
- Dirt on the coil
- Incorrect suction line size
When the refrigerant charge is low
Your air conditioner will unavoidably leak refrigerant everywhere if the lines carrying the refrigerant have holes or cracks.
Your fluid will eventually stop functioning since the compressor will have to work twice as hard to push enough refrigerant through the system to cool your space after a while if the level gets critically low due to leakage. The compressor may eventually fail as a result of the strain.
Electrical problems
Sometimes electrical failure cannot be avoided. This may lead to an accumulation of acids, which can seriously harm other components in addition to the compressor. Make sure your G2 Motorsport technician performs a test for the presence of these corrosive acids if your compressor has failed. It might not be worth fixing if they discover an electrical burnout that has damaged the entire system. Instead, they might want to replace it.
Too much refrigerant
Your compressor may stop working if a “not quite fully certified” technician, a friend, or another person working on your air conditioner mistakenly adds too much refrigerant or an inappropriate amount of refrigerant to your system.
Dirt on the coil
It makes sense that some dust and grime will accumulate on the condenser coil while you are living life and driving your car.
When enough grime accumulates, the air conditioner can no longer remove enough heat from the system and switches to running continuously in an effort to cool your car.
The compressor may overheat and stop working as a result of the elevated pressure and temperature.
Incorrect suction line size
This can be a straightforward but serious issue. An untimely breakdown of the A/C compressor can result from a line that is too big or too small for your system.
Symptoms of a Bad AC Compressor Clutch
Here are some signs you will notice if your AC compressor clutch is bad:
Loud and Weird Noises
If the AC makes a loud noise when you turn it on, a compressor might be faulty. The compressor has multiple moving parts, just like the engine. Noises are a common complaint when the clutch or another moving component starts to fail or seize.
But a high-pitched screeching sound might also be caused by a component that is damaged or leaking.
A seized bearing, on the other hand, will make a grinding noise. It’s frequently preferable to replace the complete compressor rather than attempt a repair because it can be so difficult to identify which component inside the compressor is damaged.
Increase in cabin temperature
The most typical symptom of a bad AC compressor clutch is increased cabin temperature on hot days when you really need the A/C. Whenever the cabin temperature increases unexpectedly, you should frequently check for a broken compressor.
The compressor fails as a result of the clutch being damaged since it is unable to control the refrigerant flow. Naturally, a lack of refrigerant could also be the cause of the increased cabin temperature, so a full system assessment is required.
Clutch seizes to move
The compressor pulley can connect to or disconnect from the motor using the clutch, ensuring that it only runs when it should. Action cannot proceed normally if the clutch seizes. While the air conditioning is on, check the front of the compressor to determine if the clutch is spinning.
Rrefrigerant leakage
The compressor’s bearing may sustain damage when the compressor clutch fails. Although it’s uncommon, it does happen occasionally to see fluid leaking through the front seal as a result of a broken AC compressor clutch.
Check the compressor for any signs that liquid is leaking through the front seal.
Unable to turn on or off the AC
The compressor might continue to run if the clutch is damaged, making it difficult or impossible to switch the air conditioning off. This could cause more serious issues and be bad for the other AC parts.
However, it happens much more frequently that the clutch may fail and prevent you from turning on the air. You are left without air conditioning since the compressor would not receive any power from the engine without the clutch.
Related: What is AC Pressure Switch? its Diagram and How it Works
What causes the AC Compressor Clutch Not to Engage?
Below are some of the things that could be causing your AC compressor clutch not to engage:
Incorrect Amount of Refrigerant
The proper amount of refrigerant is required for the air conditioning system to function. Although the issue could be brought on by either too little or too much refrigerant.
The modern system utilizes an AC pressure switch lockout mechanism to protect the valuable components if the refrigerant level isn’t correct.
However, the power provided to the AC compressor clutch will be cut off, and the clutch will not engage if the pressure in the AC system is too high or too low on either the low-pressure side or the high-pressure side.
Although the AC refrigerant system may have been overfilled by you or another person if the AC pressure is excessive. if the pressure is abnormally low, the AC system is certainly leaking.
Damaged or Worn Clutch
It might just be that the AC compressor clutch has worn out, just like any other clutch, and needs to be replaced. Older cars or those that have overused their air conditioning system are more likely to experience this issue.
When the clutch is newer, it won’t typically wear out. The clutch might not engage if the clutch plate is worn out.
However, it might occasionally slip, causing operations to be irregular. Some spacer shims in AC clutches can be removed in order to give the clutch a little bit more life. It might possibly be the result of a clutch coil failure, in which case the clutch coil won’t engage at all.
Failed high or low AC pressure switch
Another thing that could be the reason behind your AC compressor clutch not engaging is a failed high or low AC pressure switch. The AC system has two AC pressure switches: one on the high-pressure side and one on the low-pressure side.
These switches regulate the pressure to prevent it from going too high or too low. Even if the pressure is correct, a malfunctioning sensor may send the wrong signal to the AC compressor clutch and cause it to shut down.
Bad electrical connection
The electrical connections and wiring in your car’s AC system are many. The clutch could stop functioning if there is an issue with any of them. The 12V+ power wire to the AC clutch is the most crucial connection; if the wire is corroded or damaged in any way, the clutch won’t engage.
Blown Fuse
AC compressor clutch not engaging can also be a result of a blown fuse. The compressor may get too much voltage if there is an electrical fault in the AC system. The fuse will blow as a result of this operation.
It is better for the fuse to blow than for the system to receive too much voltage. If it occurred, the pricey AC components might suffer significant damage. The fuse for the AC clutch can be found by checking your owner’s manual.
The faulty or leaking evaporator coil
The evaporator coil is a component of the car’s air conditioning system that aids in airflow to cool the vehicle. Thus, if the coil is faulty or leaking, it could result in the AC compressor clutch not engaging.
When the heat and air conditioning are turned on, a hissing sound or bad odor indicates that the evaporator coil is faulty or leaking. The clutch will not engage as a result. You might need to swap out the evaporator coil to resolve the problem.
But keep in mind that replacing something costs a lot of money.
How to diagnose why the AC compressor clutch isn’t engaging
You should turn the A/C settings in your car all the way up to see if your AC clutch is functioning. Then, turn on the engine and look under the hood to see the air conditioner compressor.
The pulley and ac clutch spinning shows that everything is in order. There is a problem with the system if all that spins is the pulley. However, one of the causes listed above could be the culprit.
Check the condition of the belt covering the pulley on the compressor. If the belt is slipping or worn, it needs to be adjusted or replaced. Examine the area around the clutch plate for signs of rust.
If you find any, the compressor may simply need to be replaced because it is old, worn out, and broken.
Check the wiring to the clutch because improperly connected wires could affect how the compressor operates. To supply enough power, the wire must be connected and in good shape.
(In addition, the evaporator temperature sensor and high-pressure switch may be broken or have loose wires.) Your AC compressor’s fuses could be found in the fuse box. A fuse that has blown can be quickly replaced.
How to fix an AC compressor clutch that fails to engage
Here are things you should do to fix the AC compressor clutch that fails to engage:
Examine the refrigerant levels and make a correction
It is wise to start here because this is often the most prevalent issue with automotive air conditioning systems. To check whether the system has too little or too much refrigerant, use specialized gauges.
The clutch might not disengage in either case. You can recharge the system to the appropriate levels using a DIY repair kit. We do, however, highly suggest that this be carried out by professionals using the proper equipment.
Measure the voltage transferred to the AC clutch
Measuring the voltage transferred to the clutch coil is the easiest method for diagnosing an issue with the AC clutch. The AC connector in the majority of car models simply has a +12 volt cable, but occasionally you can also discover a ground cable.
The steps are straightforward: start the engine, turn on the AC, and unplug the AC clutch connector.
If everything is working as it should, you should observe 12 to 14 volts coming to this wire when you use a multimeter to measure the voltage going to the connector. You should also check the ground if there is one.
If the proper voltage and ground are visible, you can determine that the issue is either a worn-out AC clutch, a defective clutch coil, or corrosion in the clutch connector. Continue troubleshooting if there is no voltage.
Check the low and high AC Pressure Switches
The AC system’s high-pressure and low-pressure switches need to be examined next. A multimeter can frequently be used to measure them in order to check them.
But you need to get a repair manual for your specific car model to know what values to look for or when the circuit should be closed or opened.
In some cases, an OBD2 scanner can be used to diagnose the AC system in newer cars, and in this situation, the diagnostic tool can display the pressure that these sensors measure.
Jump-start the clutch
To test whether the clutch will engage manually, you can jump-start it. However, you shouldn’t attempt this until you are certain that you understand it completely, since if you do it incorrectly, you risk damaging valuable parts.
To be sure you are using the correct wire, use a wiring diagram. You would directly connect the clutch’s wire to the battery to complete this procedure.
If this is unsuccessful in engaging the clutch, a new clutch must be installed. However, installing a new AC compressor is typically the better choice. You may encounter some more uncommon problems if the clutch is engaged manually.
Instead, you might need to rectify an electrical connection, replace a blown fuse, or install a new pressure switch.
Inspect the electrical connections
Another thing that could cause an AC clutch not to engage in either a mix-up in connections or damaged wires, as we discussed above,. Connections should be checked, as the AC clutch needs an electrical connection to function.
Inspecting the power wire to the AC clutch is the best place to start since if power cannot get to the clutch, it won’t engage. The remaining wires in the system must be visually inspected in addition to this connection.
Any wire or connector that has been damaged should be replaced right away.
Check for any blown fuses and replace
Finding the correct fuse for the system is necessary before you can check the fuse. You should be able to find a diagram in the service manual for your automobile.
With the engine off, carry out the following procedures: Use your multimeter to test the functionality of the fuse once you’ve located the right one. The only thing you can do if it blows is replace it.
However, a more serious electrical issue could cause the fuse to keep blowing. It’s crucial that you replace the fuse with one of the right amperages.
How much does it cost to replace an AC compressor clutch?
The compressor is one of the most essential components of the air conditioning system, making it one of the most expensive parts overall. But replacing it is not difficult.
A number of factors, including the vehicle’s make and model, the repair shop location, and the cost of labor in your area, can affect the cost of replacing an AC compressor clutch.
An AC compressor clutch replacement can cost anywhere between $300 and $800 on average. However, the price may be higher if you need to replace the entire AC compressor and other related parts, as well as if you drive a luxury or high-performance vehicle.
A technician’s experience and the repair shop’s location can both affect how much labor costs.
Before having the work done, it is suggested that you get a few estimates from several repair shops to be sure you are getting a fair price. You can also see if the replacement of the compressor clutch is covered by the vehicle’s warranty or service contract.
Remember that this is only an estimate, so actual costs may differ. A competent mechanic should always be consulted before making any decisions.
FAQs
How do I know if my AC compressor clutch is bad?
The clutch may briefly click when the air conditioner is turned on before the belt and pulley begin to rotate. The compressor has to be serviced if the clutch does not engage or if it does so with a shrieking or whining sound.
Here are some other signs you will notice if your AC compressor clutch is bad:
- loud and weird noises.
- An increase in cabin temperature.
- Clutch seizes to move.
- Refrigerant leakage.
- Unable to turn on or off the AC.
Is it worth replacing the AC compressor clutch?
Better long-term durability is the main justification for replacing a full A/C compressor and clutch system. The AC clutch pulley may need to be replaced, but on the way out, it most likely damaged the compressor.
What does the AC compressor clutch do?
One of the most crucial components of a car’s air conditioning system is the compressor clutch. This mechanical component pushes the cool air through the system and presses the entire A/C system to make sure everything functions properly.
What causes AC compressor clutch failure?
The internal A/C system will overheat from consuming too much power, which will cause the clutch to slip against the pulley. Slipping can result in clutch failure if the compressor lacks lubrication or is overused under extremely hot conditions.
Can I drive with a bad AC compressor clutch?
Driving while your A/C compressor is broken is not a smart idea. It’s not advisable to drive your car with a damaged A/C compressor, yet occasionally you can do so without needing to have pricey repairs.
When these crucial components of your car’s air conditioning system malfunction, your engine, and even your health may suffer more harm.
Can I drive with a bad AC clutch?
Yes, you can in most cases. Remove the belt if you can if the compressor clutch assembly has frozen up.
What does a bad AC clutch sound like?
Therefore, if you turn on your air conditioner and hear rattling, your AC compressor may be faulty or damaged. Both rattling and loud humming noises from your car’s air conditioner that get louder as you accelerate can be signs that your AC compressor needs to be replaced.
Does the AC compressor affect the transmission?
The engine and transmission should continue to function normally as long as the A/C compressor is not physically damaged (broken or seized).
Can a bad AC compressor affect engine performance?
Yes, a malfunctioning AC compressor will have a significant impact on the engine. Through the provision of an air conditioning system, the AC compressor performs a very important role in the car.
The engine will be impacted if the a/c compressor is compromised because when the compressor’s pulley bearing fails, the engine will stall as a result of the stuck compressor.
Can I unplug my AC compressor and still drive?
Due to an internal issue, the compressor may jam up. You can only drive if the clutch is in working order. If the pulley turns when the clutch is disengaged, then disconnecting the clutch activation wire will allow you to drive.
How long should an AC compressor last in a car?
An air conditioning compressor can last between eight and ten years, according to estimates. Then, many drivers will claim that they won’t ever need to replace their A/C compressor because this figure represents the lifespan of the vehicle.
Can a car run without an AC compressor?
As long as you don’t want or need AC in your vehicle, you’ll be OK. Your AC pulley is a clutch-equipped free-spinning pulley. But until the air conditioning is turned on, it will spin at will. Even if the clutch isn’t functioning properly, you can still use your car.
