If you’re on this page, chances are you’ve noticed that your compressor clutch won’t engage and you can’t just make out what that means. Here, you will find all the troubleshooting techniques that will help you pinpoint the problem.
There are tons of reasons why the compressor clutch won’t engage with the most common being due to a faulty compressor clutch or a blown fuse. This article dives deep exposing the common causes and relevant fixes so you won’t have to rely on your mechanic.
Jeep Cherokee AC Compressor Not Engaging: Most Likely Causes
Blown fuse
Regardless of how your AC compressor works or receives power, it is likely connected to a fuse. The fuse would blow to protect the compressor from getting damaged due to over-current. You should start by checking the compressor clutch fuse.
Electrical issues
Broken wire connections or precisely a broken wire connecting to the clutch coil could cause the clutch not to engage. Broken wire connections could be due to a number of reasons including having recently fixed the car and accidents.
Low refrigerant
If the system is too low on refrigerant then the compressor won’t engage. However, the system can’t just run out of refrigerant in such a manner. Note that checking the AC refrigerant level would a require professional diagnosis.
You should check around the AC system using a UV kit to search for leaks. There is a likely chance that the refrigerant is leaking rather than being depleted. Also, it is possible that the leak could be from the hoses, seals, or other parts of the AC system.
Jeep Cherokee AC Compressor Not Engaging: How to Fix
Check the fuse
Start by checking the compressor clutch fuse. You might have to refer to the user manual to help you find the fuse. If the fuse is good, then you would have to check other parts like the relay. However, if the fuse is blown, then replacing it should solve the problem. IF the clutch engages after fixing the fuse, then you go ahead and turn on the AC to see if it works.
If everything gets back to normal with that fix then you should inspect the system to diagnose the cause of the blown fuse. You might have to test the system for pressure using an AC gauge.
Test the compressor clutch relay
If the fuse is good, then the next place to look would be the compressor clutch relay.
- Disconnect the electrical connector from the compressor clutch coil.
- Move it always to a safe area so you can check for power and ground.
- Ensure that the engine is running and the AC is set to Max.
- Get a digital voltmeter and check for battery voltage and also, good ground at the connector.
- If you didn’t get battery voltage, then pull the compressor clutch relay.
- Check for power and ground on the relay control coil terminals in the socket.
- Depending on the year of your car, it may trigger the relay control coil ground through the ECM or PCM.
- If the power and ground checks out in the relay socket, then you would have to test the relay.
- Simply swap a similarly sized relay. It is possible that the relay could be defective or there could be issues with the wiring harness and ground.
If the relay is working perfectly, then you should check for power and ground in the compressor clutch connector. You would need a digital voltmeter to check the terminals of the connector for full battery voltage and ground.
Check the compressor clutch coil
If the power and ground check out at the compressor clutch connector, the next step would be to check the compressor clutch coil for open and resistance. You should also check for short to ground and short to power.
You will need your meter set to the ohms scale and connect to both leads of the terminals of the clutch coil to check for coil resistance. If you don’t get a resistance value, this means there is an open in the clutch coil and it would have to be replaced.
Next is to check for short to ground. Connect one of the terminal lead to a metal contact point on the compressor and the other to one clutch coil terminal.
Switch to the other terminal. Repeat the process again. If you notice continuity during this test, then the clutch coil has short to ground. You would have to replace the clutch coil.
Recharge the system
In some cases, checking if the system is low on refrigerant should be the first step to take. This is most likely the cause of the problem if the compressor cycles on and off. If the system is low on refrigerant, the compressor won’t engage and the AC system would have to be charged.
You can charge the system on your own using a DIY kit, however, it is not always advised. If the air conditioning system is so low on refrigerant that it affects the compressor clutch, then you shouldn’t be looking for how to charge the system but rather checking for leaks.
In this case, the leak could likely be a large one and the affected part would have to be replaced. There are chances that there is moisture and air in the system. Moisture is the biggest enemy of refrigerant as it would react with it and the oil to cause acid and sludge which would cause catastrophic damage to the system.
The system would have to be fully evacuated to remove the air and moisture before being recharged. This would be a much better fix than going ahead to recharge the system with a DIY kit without checking for leaks.
Final Thoughts
While you could check the parts of the compressor clutch for power, there are chances that the clutch itself could be defective and would have to be replaced. You can go ahead with this conclusion if all other parts including the refrigerant check out.
