How To Bypass Car AC Clutch Relay – Guide

How To Bypass Car AC Clutch Relay – Guide

Understanding some basic things in your car can be the difference-maker for you and your maintenance culture.

Most people do not care much about these things and only keep driving the vehicle as long as it’s running and only take it for a checkup when the car stops running smoothly.

How to bypass car AC clutch relay

If you want to know more about cars and your AC system, you are in the right place.

This article will discuss the AC compressor AC clutch and some problems related to these two components, which can lead to AC compressor clutch failure.

You will learn the causes of these failures and how to bypass the AC clutch relay, giving you a step-by-step guide.

How To By-Pass AC Compressor Clutch Relay

With everything discussed in this article, you might think bypassing your AC clutch relay is big science.

However, you don’t need much know-how to be able to bypass your AC clutch relay, here are three methods.

Adding More Coolant

One of the common issues of a disengaging AC is a low level of coolant or refrigerant. You can solve this problem by adding more coolant.

If your engine is compatible with an R134a refrigerant, adding it to your unit will override the low-pressure switch.

It results in a normal function of your AC compressor clutch relay.

Jump-Starting Your Clutch Relay Manually

Since we are about to start discussing oil, here is a disclaimer; ensure that your AC is constantly fed with oil before repairing.

And because every AC has a different component, you must refer to your manual on filling your AC compressor oil and its preferred levels.

Disconnect The Clutch Oil Cable

We have highlighted that high or low oil pressure switches can prevent the compressor from damaging due to a bad operating situation.

So when you are trying to discover if the compressor has become bad, you need to disconnect the connector cable from its other parts.

Connect it to the connector and measure the battery voltage with a voltammeter. If the readings come back blank, it is essential to check the AC relay and fuse.

Ensure That The Compressor Has Enough Oil

You must note the importance of the oil level before engaging the clutch manually; the oil level in the AC compressor is visible through the glass display.

Check if the oil level is above the red line. If there is no sufficient oil, ensure you add more oil.

Kindly note that you need to consult the manual to ensure that the oil is the exact spec recommended.

Set The Refrigerant

The manufacturers are always precise with the amount of refrigerant in the AC compressor; therefore, check the refrigerant to ensure it has the proper amount.

Enough refrigerant prevents the compressor parts from being damaged.

Furthermore, you need to measure the refrigerant using a pressure gauge installed directly on the air conditioning’s high pressure and low-pressure rail.

After that, compare it with the recommended value by the manufacturer and then try to balance it.

Bypass The Relay

After you have gone through the first three steps, you need to ensure that you know how to engage the clutch manually.

Just at the compressor front, you need to unplug the single wire connector by the side.

After doing that, then attach a wire to the wire you have just disconnected from your compressor.

After doing that, you have to attach the jumper wire to the wire you have just disconnected from the compressor.

Then attach the other end of the jumper wire to the positive side of the battery. It will then start up the compressor manually.

Bypassing car AC clutch relay

Change Your Clutch

The moment every other method fails, you have to resolve to change your clutch. In most situations, the electromagnetic coil controls the AC compressor.

The moment the current flows through the coil, it immediately creates a magnetic field, pulling the clutch plate towards the pulley, which engages the compressor.

The moment you have a constant failure in this process, the recommendation is to change.

Even though we are interested in ensuring you can jump-start your clutch relay, we are also aware that a situation calls for replacing a damaged component.

It might be best to replace instead of repair to avoid further damage.

Kindly note that the AC clutch is part of the AC compressor; it is the main component in the air conditioning system, which means that that system needs to be always properly maintained and frequently checked.

So avoid repairing if the best solution is to change it.

Important Note

  1. Route the jumper: Route the jumper wire so that I won’t get tangled with the other moving component.
  2. Replacing the clutch: When using your vehicle, if you have a consistent issue with your AC clutch, for instance, when the clutch is engaging, but the compressor is unable to spin, at this point, the best option might be to change the compressor clutch altogether because a bad AC compressor clutch needs immediate attention or fixing before it becomes severe damage to the air conditioning system and the engine.
  3. Avoid switching your AC on and off so frequently. It can result in overheating and damage to the AC compressor.
  4. It is essential to allow those with technical experience and expertise to handle every electrical component in your vehicle, to avoid further damage to the compressor.
  5. Chattering and racing will continue in-between the contact whenever there is a contact. And the moment the fluctuation in the voltage applied to the coil becomes large. And this may result in a situation where the relay contacts are frequently switched.

What Are The Things Responsible For The AC Relay Failure?

Check The Clutch Relay Sensor

Many modern cars usually have their AC relay switched on and off using high-pressure, low-pressure switches, including the compressor oil level.

If any of these three components are damaged, the relay will not be engaged.

Burnt Fuse

Another critical thing to note is the fuse, most cars have a fuse box, and most people are not aware of it; it can be located in the bonnet of your vehicle and below the steering.

You can open the box and locate the AC fuse; they are all labeled, so you should find it easily.

After finding it, test it with a multimeter to ensure it is working. You can also use this same technique to test the AC clutch relay.


The AC clutch relay is a device that ensures that the compressor engages and disengages from the vehicle engine.

Bypassing the clutch relay of an air conditioner is not complex.

However, there are things you have to know to ensure that you can effectively jump-start the compressor by bypassing the relay.

We have listed steps you need to take to get this done. However, do not ignore some things that show a sign of the compressor being faulty.

A routine checkup can be a beneficial culture for your vehicle. You will be able to spot problems before they escalate into something more damaging.