When my LG air conditioner stopped working during a hot summer week, I felt lost. The room was getting hotter by the hour, and I had no idea why the cool air had stopped. The fan was running, but the air wasn’t cold. After checking everything I could think of, I realized the compressor wasn’t turning on. If you’re facing the same problem, I want to share what I learned. I’ll explain the causes, how I fixed mine, and what you can do to get your AC working again.
How An Air Conditioner Compressor Works
First, let me explain what the compressor does. It’s like the heart of your AC. The compressor pushes refrigerant through the system. This is what lets your air conditioner take heat from your room and send it outside. If the compressor doesn’t turn on, you only get air movement, but not cool air.
When my LG AC failed, I heard the fan, but the outside unit was quiet. No humming, no clicking—nothing. That’s a big sign the compressor isn’t starting up.
Common Reasons Why The Lg Compressor Won’t Turn On
I learned that many things can cause this problem. Some are simple, some are not. Here’s what I found out when I searched, talked to technicians, and tried to fix it myself.
1. Power Supply Issues
One of the first things I checked was the power. If there’s no electricity, nothing will work.
- Check if the AC is plugged in all the way.
- Look at the circuit breaker or fuse box. Sometimes, a blown fuse or tripped breaker is the only problem.
- If your LG AC has a reset button, try pressing it.
When I checked mine, I found the breaker had tripped. I switched it back, and the AC started. But if yours keeps tripping, something bigger could be wrong.
2. Faulty Capacitor
The capacitor helps the compressor start. If it goes bad, the compressor won’t turn on.
- You may hear a humming sound, but the compressor doesn’t start.
- If the capacitor is swollen or leaking, it’s probably dead.
In my case, the capacitor was fine. But I’ve seen other units where a new capacitor fixed the problem. If you want to replace it, turn off the power first. Capacitors hold a charge even when the AC is off, so be careful.
3. Thermostat Problems
The thermostat tells the compressor when to turn on. If it’s broken or not set right, the compressor stays off.
- Make sure the thermostat is set to “cool” and the temperature is lower than the room.
- Try changing the batteries.
- Sometimes, the wires behind the thermostat get loose.
Once, I set my thermostat to “fan only” by mistake. No wonder the compressor didn’t work! Small details like this can save you time.
4. Dirty Or Blocked Filters And Coils
A dirty air filter or coil can block airflow. If the unit gets too hot, it might shut off the compressor to protect itself.
- Clean or replace the air filter every month.
- Check for dust and dirt on the coils.
When I opened my LG unit, the filter was full of dust. After cleaning it, the compressor kicked in again. This is a simple fix I now do regularly.
5. Faulty Control Board Or Relays
The control board is like the brain of the AC. If it’s faulty, it may not send the signal to turn on the compressor.
- Burned marks or smells on the board are a big red flag.
- Sometimes, the relays (small switches on the board) fail.
I couldn’t check this myself, so I called a technician. He found a bad relay and replaced it. After that, the compressor worked fine.
6. Low Refrigerant Level
If your AC has a refrigerant leak, the pressure gets too low. Many LG models have a safety switch that stops the compressor if there’s not enough refrigerant.
- You might hear hissing sounds.
- The AC might blow warm air.
Refrigerant is not a DIY fix. You need a pro for this. If you keep adding refrigerant without fixing the leak, the problem comes back.
7. Compressor Failure
Sometimes, the compressor itself is dead. This is not common, but it does happen, especially with old units.
- You may hear clicking, but nothing happens.
- The compressor may start, then shut off quickly.
If the compressor is bad, it usually costs a lot to fix. I was lucky—mine was fine. But a neighbor had to buy a new unit after her compressor failed.
Step-by-step Troubleshooting: What I Did
Let me walk you through what I did when my LG compressor wouldn’t turn on. Maybe it will help you, too.
Step 1: Check The Basics
First, I made sure the AC was plugged in and the breaker wasn’t tripped. I pressed the reset button. Sometimes, a simple reset is all you need.
Step 2: Listen And Look
I stood next to the outside unit. Was it making any sound? Was the fan turning? I looked for signs of power. If the fan runs but the compressor is silent, it’s a clue.
Step 3: Thermostat Settings
I checked the thermostat. Was it set to “cool”? Was the temperature low enough? I changed the batteries, just in case.
Step 4: Clean The Filter
I pulled out the filter and saw a thick layer of dust. I cleaned it and put it back. This small step made a big difference.
Step 5: Call A Technician
When these steps didn’t fix it, I called a pro. He checked the capacitor with a meter. He also checked the control board. In my case, the relay on the board was burned.
Table: Quick Troubleshooting Guide
Here’s a simple guide for what to check if your LG compressor won’t turn on.
| Problem | What to Check | DIY? | Who to Call |
|---|---|---|---|
| No Power | Plug, breaker, reset button | Yes | Electrician if problem persists |
| Bad Capacitor | Bulge, leak, hum sound | Maybe (if careful) | AC Technician |
| Thermostat | Settings, batteries, wires | Yes | AC Technician if needed |
| Dirty Filter/Coil | Dust, airflow | Yes | AC Technician for deep clean |
| Low Refrigerant | Hissing, warm air | No | AC Technician |
| Compressor Failure | No sound, clicks, short cycles | No | AC Technician |
Table: Compressor Not Turning On – Possible Symptoms
| Symptom | Likely Cause | Easy Fix |
|---|---|---|
| Fan runs, no cool air | Compressor, capacitor, refrigerant | Check power, clean filter |
| No fan, no compressor | Power loss, control board | Check plug, breaker, reset |
| Compressor hums, does not start | Bad capacitor | Replace capacitor |
| Unit starts, then stops fast | Compressor failure, low refrigerant | Call technician |
Table: Diy Fix Or Professional Help?
| Task | DIY Level | Tools Needed | Risk |
|---|---|---|---|
| Cleaning filter | Easy | None | Low |
| Replacing capacitor | Medium | Screwdriver, gloves | Medium (shock risk) |
| Checking thermostat | Easy | None | Low |
| Repairing compressor | Hard | Special tools | High (call a pro) |
Non-obvious Insights I Learned
Here are two things I didn’t know before my LG compressor problem:
- Voltage Fluctuations: My area has unstable voltage. Sometimes, the compressor won’t start if the voltage drops, even if the rest of the AC works. I added a voltage stabilizer and it helped a lot.
- Overload Protector: Many LG units have a small part called an overload protector. If the compressor gets too hot or the current is too high, this part cuts the power. It resets itself after cooling down. But if it fails, the compressor will never turn on—even if everything else is fine.
What Not To Do (from My Mistakes)
- Don’t keep restarting the AC hoping it will work. This can damage the compressor.
- Don’t open up the AC unless you know how to stay safe around electricity.
- Don’t add refrigerant yourself. It’s dangerous and often illegal without a license.
When To Call A Professional
If you’ve checked the basics (power, filter, thermostat) and the compressor still won’t turn on, it’s time for help. I wasted two days trying to fix things I didn’t understand. A good technician can find the problem fast. They have special tools to test the capacitor, check the control board, and measure refrigerant levels.
How Much Does Compressor Repair Cost?
Prices can vary a lot. For my LG unit, the technician visit was about $60. Replacing a relay or capacitor cost me $30–$70. A full compressor replacement can be $400 or more. Sometimes, it’s better to buy a new AC if the compressor is dead and the unit is old.
How To Prevent Compressor Problems
After my experience, I now do these things to keep my AC running well:
- Clean or replace the filter every month.
- Get a pro to check the AC once a year.
- Use a voltage stabilizer if your power is unstable.
- Don’t block the airflow around the outdoor unit.
These steps keep the compressor cool and help it last longer.
Frequently Asked Questions
Why Does My Lg Air Conditioner Fan Run But The Compressor Does Not?
This usually means there’s power to the unit, but something is stopping the compressor. It could be a bad capacitor, a thermostat issue, or a safety switch. Try cleaning the filter and checking the thermostat settings first.
Can I Replace The Compressor Myself?
I don’t recommend it. Compressors are heavy, expensive, and need special tools to replace. It’s easy to make a mistake and damage the unit. Call a trained technician for this job.
How Do I Know If My Capacitor Is Bad?
A bad capacitor often makes a humming sound, and the compressor won’t start. If you can safely open the unit, look for bulging or leaking on the capacitor. But be careful—capacitors can shock you even when the power is off.
What Is An Overload Protector, And Can It Fail?
The overload protector is a safety part that stops the compressor if it gets too hot. If it fails, the compressor won’t turn on. It’s not easy to check unless you have the right tools, so a technician should do it.
Where Can I Get More Help For Lg Air Conditioner Problems?
You can find helpful guides and support at the official LG Support Center. They have manuals, troubleshooting tips, and contact info for service.
Staying cool in summer is important. If your LG air conditioner compressor isn’t turning on, don’t panic. Start with the simple checks I shared. If you’re not sure, call a pro. Learning from my mistakes can save you time, money, and sweat.
I hope my experience helps you get back to cool comfort soon.
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