How To Test AC Clutch Relay: A Step-by-step Guide!

Testing an AC clutch relay is indispensable to ensure the AC system’s good function.

You’ll be more secure and enjoy the best air conditioning owing to any flaw treated timely. But how to test AC clutch relay properly?

The procedure is relatively easy and quick, with a few simple steps.

By testing the AC compressor clutch relay, you can identify any problems that may be occurring and take the steps needed to repair them, saving you time and money.

Look no further than this post! Read on!

How To Tell If AC Relay Is Bad?

How To Test AC Clutch Relay

How to know if AC relay is bad? Here are 6 common sure signs of a faulty AC relay:

The Compressor Is Not Switching On

How to tell if AC relay switch is bad? If the compressors are not turning on, it might be a symptom of trouble with the air conditioner clutch relay.

You can generally hear the compressor kick on when the AC is on.

Commonly, a clicking sound also pops up as the clutch engages. Turning the key on with the clutch-engaging sound suggests that power is insufficient due to a faulty relay.

Spike In Energy Consumption

Rising energy costs are a direct result of a compressor unit’s dysfunction. Your air conditioner’s extended cycles stem from its incapacity to keep the ideal temperature on the thermostat.

Of course, this will end up with increased energy usage.

Inconsistent Cooling

The AC compressor relies on the current from the relay. The AC system can’t deliver cold air adequately if it is not operating fine.

When an AC relay begins to fail, it may supply insufficient or erratic power to a compressor, resulting in subpar or nonexistent cooling.

In some cases, the AC will work efficiently, but in others, it may fail to turn on, offering uneven cooling. Perhaps, the relay is about to break down.

Faulty Compressor Clutch Coil

Common causes of coil failure include exposure to ambient temperature and humidity variations.

The malfunction is also due to moisture, a short circuit (because of corrosion) between turns, or the voltage inside the coil and clutch being greater than 110% of the specified value.

Coil insulation degradation and improper connections are two more potential causes.

Unwanted Noise

When a system component breaks, it usually takes more time or energy to get going. A relay switch that isn’t working correctly may make a rattling noise when it attempts to turn on.

There are tons of possible factors contributing to failure in a relay’s electromagnetic components.

Test the clutch operation, clutch-type AC compressor, engine coolant temperature, air temperature actuators, and even ambient air temperature sensor if possible.

No Cold Air

This is one of the bad AC relay symptoms. AC may stop blowing cold air; perhaps your relay has burned out. The AC can’t create cool air if the relay fails to work.

Several things might go missing, but a failing relay is one of the most typical culprits behind an AC’s cold air loss.

We advise getting an expert AC system diagnosis if you are experiencing trouble and fear your AC relays have collapsed or are about to break.

Should it be determined that your AC relay is defective, they can carry out the best solutions or substitute it for you.

Perhaps, a faulty AC clutch relay also relates to the abnormal AC turning on and off and the car AC stopping working in the hot weather. Diagnose the culprits and try to have them all fixed soon!

Air Conditioner Repair: How To Test AC Clutch Relay?

How to test A/C relay

How to test A/C relay? We will walk through the inspecting step before getting the instructions with different tools:

How To Inspect

To examine the relay, take the following actions:

  • Turn off the engine before removing the relay.
  • Hold it firmly, and pull until the object is removed.
  • If it is too tight, twist it to loosen it up.
  • Remove the relay and give it a close inspection.
  • Search for just any corrosion hints. The bottom should be flawlessly clean. If not, wipe all the relays immediately.
  • Examine the terminal from which you have removed the relay.
  • If you notice melted plastic, the terminal housing was likely overheated and melted.
  • The relay has to be changed in this situation.
  • When there is only light rust, it may be cleaned off with a buff and put back to use.

How To Use A Multimeter

Electrical or ECU issues in automobiles are identified with a multimeter. In addition to other things, it accomplishes this by monitoring voltage, current, and resistance.

You can figure out why specific auto features are malfunctioning or not operating as well as they should.

The relevant circuit board sockets accept the probes after being inserted. One of these plugs has a relay attached to it.

Using a multimeter, you may check the operation of automobile relays. The relay ought to click as soon as electricity is introduced. In the absence of it, an open circuit exists.

How To Use A Relay Tester

Problems, including power outages, defective wiring, and corroded grounding, may all be identified using a relay tester.

The relay(s) in a given relay kit will activate in response to the presence of a key in the ignition.

A pilot light will go on to verify the operation. When the bulb glows, the circuit is active and functioning as intended.

Your relay tester will transfer a signal from a gadget with a circuit board. For instance, it relays information from a pressure sensor to a controller for a component like an electric gasoline pump.

To do this, a tester will take charge of the original relay using its own.

For the tester to function, it is necessary to hook up the battery and the circuit board. To utilize the device, just clip an alligator clip from the tester onto a wire along either side of the PCB.

How To Adopt A Jumper Harness

A jumper harness enables an automotive repair technician to test the electrical system while diagnosing and troubleshooting problems.

Instead of separating the fuse box and pulling out individual fuses, you can take the whole panel out and replace the fuses all at once.

All of the car’s fuses are stored in the fuse box, to which the fused jumper harness attaches. It consists of a cable linking the battery to the starting solenoid.

The wires are held together using a clamp. They are routed through the engine bay to their ultimate destination.

You can find the source of electrical issues by following the lines from one possible reference to another.

Since the battery cables are too short, adopt a set of jumper wires. The new relay receives electricity from the battery sent via the cables.

They are necessary since the new relay will only function effectively if it gets electricity.

How To Examine My AC Relay Fuse & Switch?

How To Test AC Relay Fuse

Relays for AC units are simple devices that guard them against harm. In the event of a current overload, they are intended to shut off the circuit. By doing this, a high current won’t hurt your AC unit.

You will want a multimeter to examine an AC relay. Set the suitable Ohm range for your multimeter. On the relay’s two terminals, place the probes.

The relay operates correctly if the reading is infinite. Change the AC relay fuse when it goes wrong, and the reading isn’t infinite.

How To Test AC Relay Switch

Checking the relay switch can be the first step in getting the AC up and running if it isn’t. An AC relay switch may be tested as follows:

1. Ensure your air conditioner is off.

2. Seek your relay switch. It is often placed close to the AC compressor.

3. Using a multimeter, check the relay switch for continuity when you’ve located it.

4. Change it if it is not operating correctly.

5. Afterward, turn on the AC to test its functionality.

If it does, fantastic! Otherwise, you should look into the other parts of your AC system to see what’s wrong. While you have trouble with this stuff, contact the auto service & repair for help.


Are All Relays Similar?

No, every relay is different. No matter how many or where the terminals are located, how the relay works will differ. It must function with compatible systems or devices.

If misused, some relays have the potential to spike the voltage on a 12-volt system by more than 100 volts.

How Often Does Your AC Relay Go Bad?

There are several causes for an AC relay to fail. Age and wear and tear are the most typical causes.

The relay’s contacts could deteriorate over time, which reduces their ability to make and break electrical connections.

This may ultimately result in the relay entirely failing. The contamination of an AC relay is another frequent source of failure.

The connections in the relay may be unable to form a solid connection if they are covered in debris, dust, or other foreign elements.

This may eventually break down the relay. It’s crucial to get your AC relay inspected by a skilled expert if you believe it could be malfunctioning.

They can spot the issue and decide whether a repair or replacement is necessary.

Where Is My AC Compressor Relay?

It can be complicated to come by, unfortunately. This relay can be found in the AC’s control panel or the engine compartment next to the AC’s compressor.

Please refer to your owner’s handbook if you need help locating your compressor relay.

After you find the relay, test it to see whether the part functions well. When your compressor relay is OK, but the compressor still won’t turn on, there may be another problem.

How Can I Bypass My AC Relay?

You can get around an AC relay in multiple ways. The use of a bypass capacitor is one method. This capacitor is linked in series with the relay coil.

This enables the electricity to skip the relay coil and go elsewhere. A diode can also be used to get around an AC relay. This and the relay coil are linked in series.

The relay coil is not used since the diode allows current to flow only in one way. Next, a transistor is the final strategy for avoiding an AC relay.

The relay coil is bypassed until the current passes through the transistor.

The Bottom Line

Testing an AC clutch relay is a simple process helping you diagnose a problem with the AC system. It pays to test the AC clutch relay and check the compressor before taking any AC repair.

We’ve just compiled the steps on how to test AC clutch relay detailedly, including the required tools and thorough guides with different approaches.

Hopefully, our sharing will aid you in making things back to normal the right way. Share the post with others in the same boat!

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