How to Test a Car’s AC Pressure Clutch

car AC buttons

An AC compressor clutch can fail for several reasons. In most cases, this happens if you use the wrong clutch oil and the wrong coolant. However, the clutch could still fail even if you use the right oil and coolant. One of the main causes of a failed clutch is a clogged refrigerant circuit. The other causes may be detached cables or failed fuse in models that use a fuse.

Whichever the cause of the failed AC compressor clutch, you should be certain about the problem at hand before trying to solve it. In this piece, we look at compressor clutch diagnosis methods. We'll also look at the available solutions to the various problems that the clutch could be having. Finally, we'll consider whether it's possible to jumpstart the clutch and how to go about it.

Troubleshooting the AC Compressor Clutch

car AC clutch

If you're having trouble with your AC compressor clutch, there are a few methods you can use to determine the problem. Some of these procedures are quite complex and may be troublesome for those with limited mechanical skills. Below are some of the ways to check if your AC compressor clutch has a problem.

Max out Your AC Controls

In this approach, start by setting your AC controls to the maximum. Once the controls are at the max, start the engine and check the front side of the engine. Examine its condition to see if it's okay.

You want to find out whether the clutch and pulley are running. If it is only the pulley that is spinning, chances are that the compressor clutch is having a problem. Among the issues that the clutch could be experiencing include a blown fuse, bad clutch oil, an open wire, or low-pressure lockout.

Detach the Connector Cable From Clutch Oil

deconstructed car AC clutch

The other method of diagnosis involves detaching the connector cable from the clutch oil. In this approach, keep the disconnected connector safely away from all the other components.

At this point, you now want to use a voltmeter to measure the ground and voltage of the battery. If you cannot find a reading, check the fuse. If you find that the fuse is okay, check the clutch relay.

How to Solve The Problem

The two approaches above will give you a clear picture of the status of your AC compressor clutch. Once you determine the problem solving, it is a bit easy. Given that a problematic clutch could be caused by myriad issues, as seen above, the solutions also vary greatly.

Below are some of the steps you could take to solve the problem.

Add More Coolant

blue coolant going into a car

Adding coolant could be a quick and easy solution. This is probably the most common solution when an air conditioner compressor clutch is not working.

This happens often when the refrigerant levels are lower than recommended. Before you take any other steps, make sure you have checked the coolant levels and topped up with the recommended coolant.

Jump-start The Clutch

The second method and the most complex is to jumpstart the clutch. The question asked by our DIYer is whether it is possie to jumpstart the clutch and how to go about it. While the process of jumpstarting most cars is not difficult, older car models may have a different approach.

Before you jumpstart the clutch, examine the oil levels in the compressor. Add some oil if you note that the available oil is below the recommendations.

Once you have the oil at the recommended levels, start working on jumpstarting. Be careful since we are dealing with electrical components here. Start by unplugging the single wire connector on the front of the compressor.

Take the fused jumper cable and connect its one end to the side of the cable that was connected to the compressor.

Now attach the other end of the jumper wire to the positive terminal of the battery. The wire should directly supply power to the compressor clutch allowing it to engage. You do not have to switch on the air conditioner when doing this.

With that, you have a solution to the problems caused by the AC compressor clutch. If your compressor clutch stops working, just follow any of the above procedures to restore sanity.

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