What Causes a Car's Air Conditioning Compressor to Not Shut Off?

[DeKiara]

Here are the reasons why a car's air conditioning compressor does not shut off: 1. The car's air conditioning temperature is set too low, causing the compressor to run continuously. 2. The temperature sensor is faulty, leading to the compressor not shutting off. 3. The thermostat on the air conditioning unit's control board is damaged, resulting in the compressor running non-stop. 4. There is a refrigerant leak in the air conditioning system, causing insufficient cooling and the compressor to operate continuously. Below are the troubleshooting methods for a car's air conditioning compressor that does not shut off: If the cooling system works normally after turning on the air conditioning, the issue is likely a faulty thermostat, and the thermostat system should be inspected. Check if the temperature sensing tube connected to the thermostat has come loose. If it has, reattach it to its original position. Over time, the internal contacts of the thermostat may fuse, causing the control fluid inside the thermostat to leak and the thermistor in the electronic thermostat to degrade.

[ManuelRose]

When fixing my car, the AC compressor wouldn't turn off, which was quite annoying. It might be due to a faulty thermostat that fails to detect when the cabin is cold enough, causing it to keep running, or low refrigerant levels leading to low pressure, forcing the compressor to work overtime to compensate. Electrical issues are also common culprits, such as a stuck relay that won't disconnect or loose plugs causing poor contact. This constant strain on the compressor is bad for the car, draining the battery faster, increasing fuel consumption, and accelerating component wear. I did a simple check by unplugging it to see the fan, but professional repair is the most reliable solution. It's best to get the AC system checked early to prevent blockages, with regular cleaning once a year making maintenance much easier. In short, address issues promptly to avoid small problems turning into big ones.

[SanEliza]

Last time my car's AC compressor wouldn't stop running, making it unbearably cold. I suspect the temperature sensor failed, making the system think the cabin wasn't cool enough, so it kept the compressor running non-stop. Alternatively, the low-pressure switch might be stuck, interrupting the signal to stop. This is really troublesome on long drives - it increases fuel consumption, the AC noise gets loud and affects driving. I tried setting the temperature higher to see if it would stop, and checked the fuse box for issues. If it can't be fixed, it's better to spend some time at the workshop for diagnosis to avoid bigger costs later like premature battery death or compressor failure. New car owners shouldn't panic - try simple adjustments to settings and regular AC maintenance first, it might help.

[Sá]

Common issues with compressor not stopping during maintenance. Thermostat failure or insufficient refrigerant with high pressure differential are key causes; circuit faults such as relay welding can also cause continuous operation. I usually start by testing the pressure ports and using a meter to check sensor resistance to identify the source; minor repairs like replacing fuses can easily solve the problem, while major issues require inspecting the entire electrical system. Regularly checking refrigerant levels and pipeline seals for prevention can significantly reduce the frequency of this fault.