Nothing annoys on a hot afternoon than the air conditioner turning on and off after every 5 – 10 minutes, right? So, does your air conditioner turns on by itself, and you wonder why?
The air conditioner may turn itself on due to an oversized unit, Energy Saver or Sleep Mode, dirty air filter or coils, or wrongly placed or bad thermostat. Other issues include a dirty compressor, tripping safety switch, frozen coils, clogged drain, low refrigerant, or faulty wiring or component.
The AC components in this case that could fail and cause the unit to turn on and off include the compressor, condenser, relay blower motor, cooling fan, or electric control board (ECB).
Some of these components fail from short circuiting while others from breaking and wearing. I’ll discuss them to let you know what to check when your air conditioner turns on and off at will.
Let’s jump into it!
In a rush? Below is a quick troubleshooting guide when your AC repetitively turns on and off.
Air Conditioner Turns On and Off by Itself (Quick Troubleshooting Guide)
| – | Likely Reason | Quick Fix |
| 1. | Oversized Unit | Ensure your air conditioner matches the room size. Refer to the table shared in this guide |
| 2. | Energy Saver or Sleep Mode | Disable Energy Saver and or Sleep Mode functions |
| 3. | Dirty Air Filter | Replace the dirty air filter |
| 4. | Dirty Condenser Coils | Clean the condenser coils if they are dirty |
| 5. | Wrongly Placed Thermostat | Reinstall the air conditioner in a centralized location away from direct sunlight or in the extra hot rooms. If not, upgrade the capacity |
| 6. | Malfunctioning Thermostat | Change the thermostat’s batteries but if the thermostat still malfunctions, contact an HVAC expert |
| 7. | Dirty Compressor | Examine the compressor for dirt clogging and dust it off (or clean it) if it’s dirty |
| 8. | Tripping Safety Switch | Replace a tripping breaker or blown fuse |
| 9. | Frozen Coils | Have an HVAC expert inspect the AC for refrigerant leakage. You defrost the coils by fixing the leakage |
| 10. | Clogged Drain Line | Clean the drain line from clogging to improve its drainage |
| 11. | Low Refrigerant | Have an HVAC expert inspect the refrigerant level, fix the leakage source, and refill the refrigerant |
| 12. | Electrical Fault | Have an expert electrician check the air conditioner’s electricity supply cables for faults and fix them |
| 13. | Failed Compressor, Fan, Condenser, Relay, Blower Motor, Timer, or ECB | Replace the compressor, fan, condenser, relay, blower motor, timer, or ECB (Electronic Control Board) if faulty. Have an expert inspect them and render the diagnosis |
Why Your Air Conditioner Turns On by Itself and Its Troubleshooting
Below are 13 reasons why air conditioners automatically power on and off. One of these reasons could be the problem with your air conditioner.
1. Oversized Air Conditioner
If your air conditioner is newly installed and won’t stop turning on and off, there’s the chance it’s oversized. If it is, it’s likely to short cycle, thus unable to cool your space evenly.
Fix
Verify that your air conditioner is the right size for your room. Below is a table you can use on most AC models, including GE, TCL, Amana, Midea, Frigidaire, Haier, Whirlpool, and Amazon Basics.
| Maximum Room Size | AC Capacity |
| 150 sq. ft | 5,000 BTU |
| 300 sq. ft | 7,000 BTU |
| 350 sq. ft | 8,000 BTU |
| 400 sq. ft | 9,000 BTU |
| 450 sq. ft | 10,000 BTU |
| 550 sq. ft | 12,000 BTU |
| 700 sq. ft | 14,000 BTU |
| 1,000 sq. ft | 18,000 BTU |
| 1,200 sq. ft | 21,000 BTU |
| 1,400 sq. ft | 23,000 BTU |
| 1,500 sq. ft | 24,000 BTU |
2. Active Energy Saver or Sleep Mode
If the Energy Saver function is on, the AC may go off and turn itself on to save energy. This is not a malfunction; the same goes for the Sleep Mode. Sleep Mode makes the AC inactive, more like it’s not powered when it actually is.
Fix
Disable Energy Saver or Sleep Mode if any of them is active.
3. Dirty Air Filter
Once the air filter clogs, it restricts proper airflow and may cause the Ac system to short cycle. Once that happens, the air conditioner may turn on and off.
Fix
Check the air filter for possible dirt clogging. If it’s dirty, wash it if it’s reusable (or replace it). Learn to replace the air filter as often as possible, even monthly.
4. Dirty Condenser Coils
Dirty condenser coils have the same effect as a dirty air filter; they restrict airflow and can cause the Ac system to short-cycle. Once the system short-cycles, it’s unable to run uniformly.
Fix
Also, inspect the condenser coils for dirt clogging. Clean them or hire an HVAC professional to help you if they are dirty.
5. Wrongly Placed Thermostat (Wrong Locations)
The thermostat directs the air conditioner to turn on and off. If you place it in the wrong location, it will send an inaccurate reading causing the air conditioner to turn on and off at the wrong time.
Wrong locations include under direct sunlight, in the hottest room (such as the kitchen), or near air vents. These locations may cause the thermostat to read and relay the wrong reading.
Fix
Choose the right location (centralized locations) to reinstall the air conditioner if it was placed in the wrong place. Ensure it’s not under direct sunlight or in a hot room.
If that’s the case, increase the ACs capacity by 4,000 BTU for kitchens and 10% for extra sunny rooms.
6. Malfunctioning Thermostat
It’s not just the wrong location of the thermostat that could cause the AC to power on and off but also if the thermostat is faulty. A malfunctioning thermostat won’t relay the correct temperature reading. So, the AC will get the wrong signals which may cause it to turn on and off.
Fix
Try replacing the thermostat’s batteries and rebooting the AC. But if the thermostat is still malfunctioning, have an expert check it.
7. Dirty Compressor
Whenever the compressor is dirty, the air conditioner may overheat, and once it does so, it goes into a temporary self-shut phase. That explains why the AC turns on and off after every 5 or 10 minutes.
Fix
Check the compressor to see if it’s dirty. If it is, clean it.
8. Tripping Safety Switch
The air conditioner may turn on and off because the circuit breaker keeps tripping or the fuse is blown. Both cases suggest a possible overheating or electrical fault.
Fix
Check the breaker and replace it if it continues to trip. Also, replace the fuse if it lacks continuity (when you run it through a multimeter test).
9. Frosty Evaporator Coil
This issue often relates to refrigerant leakage. Once the refrigerant level drops, the evaporator coils may freeze up, and when they do, the AC may power off and on repetitively.
Fix
Inspect the outdoor unit to see if the evaporator coils are iced-over. If they are, have an expert check the AC for possible refrigerant leakage and fix it.
10. Clogged Drain line
Most air conditioning units use the ‘Float Switch’ mechanism to turn off the unit when water fails to drain correctly. So, that could be why your AC turns itself on and off every 5b or 10 minutes.
Fix
If you can, check the drain line from clogging and clean it. However, talk to an HVAC expert if you cannot unclog it.
11. Low Refrigerant
Sometimes the air conditioner may be powering on and off because the refrigerant/coolant level is low. The unit depends on the refrigerant to run and cool your space evenly. But if it leaks, perhaps due to damage to the AC or wrong installation, the AC won’t run uniformly.
Fix
Checking and refilling the refrigerant is not easy. You need an HVAC expert’s help here.
12. Electrical Fault
An electrical fault could also be why your air con won’t run smoothly. Due to faulty wiring, the AC may short cycle, and once that happens, it’s likely to power on and off by itself repetitively.
Fix
Unless you have some knowledge of faulty wiring, it may be hard to diagnose an electrical fault. So, you need a professional electrician’s help here to inspect and fix the AC’s electricity supply cables.
13. Air Conditioner Turns On Every 10 Minutes Due to Failed Component
Lastly, the air conditioner could be turning on every 10 minutes due to a failed AC component, and the most likely culprits are:
- Fan – If the cooling fan is broken, it’s unable to blow air properly, and as a result, the AC may turn on and off.
- Compressor – If the compressor is overheating for whatever reason, the air conditioner will go off and may turn on when it cools. That may happen because the compressor is failing.
- Condenser – A faulty condenser cannot relay cooling power to the AC, and the AC may therefore shut down and turn itself on.
- Relay – A defective relay could also cause the AC to turn itself on and off for failing to relay adequate power to the AC.
- Blower motor – If you have a car AC that turns on and off, the issue could be a defective blower motor.
- Timer – A malfunctioning timer may cheat the AC into turning on and off when it shouldn’t.
- Electronic control board (ECB) – The air conditioner malfunctions if the ECB board is faulty. An expert can help you check it.
Fix
The above components may be hard to diagnose when faulty. So, consider talking to a local HVAC expert. But overall, you’ll need to replace the defective part.
Window Air Conditioner Turns On by Itself
Several issues could be causing your window air conditioner to turn on and off. They include the following:
- The air conditioner could be too big for your room size
- Active Energy Saver or Sleep Mode
- Dirt-clogged air filter or condenser coils
- Iced over evaporator coils
- Wrongly positioned or defective thermostat
- Tripped or faulty safety switch
- Refrigerant leakage
- Faulty wiring
- Faulty compressor condenser, relay, fan, blower motor, or electronic control board
The Car Air Conditioner Turns On by Itself
A car’s air conditioner may turn itself on and off due to any of these issues:
- The refrigerant level is low
- The air filter is filthy
- Wrong placement of the air conditioner
- Wrong setting such as Energy Saver or Sleep Mode
- The air intake is congested (restricted airflow)
- A broken fan
- The car needs tuning-up
- One major component (compressor, condenser, timer, or ECB) could be faulty
Overall, consider having your car’s AC checked during the car tune-ups and servicing. You are likely to note and prevent an AC issue in time.
Air Conditioner Turns On Every 5 Minutes
The air conditioner shouldn’t turn itself on and off every 5 minutes. Sometimes, however, it may do so, and the reasons for that include the following:
- A malfunctioning or wrongly positioned thermostat
- An oversized unit (one that’s too big for your space)
- Energy Saver or Sleep Mode
- Clogged air filter or condenser coils
- Low refrigerant (primarily due to leakage)
- Wiring fault (involving the ACs electricity supply cable)
Closing Thought
Now you know what to check when your air conditioner turns on by itself. Therefore, consider the 11 issues when trying to troubleshoot the unit.
As seen, you can do the majority of fixes, and you only need an expert’s help in a few of them, especially those involving part replacement and electrical wiring.
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