The AC clutch cycling switch is a very important component to a modern vehicle’s AC system. It is mounted in the low pressure side of the AC system and its purpose is to detect the flow of refrigerant in the system by measuring the pressure. When it is detected that the pressure has dropped below a certain threshold, the switch will activate allowing pressure from the high pressure side of the AC system to enter the low side and equalize the pressure. When the pressure returns to normal, the cycling switch will close. The pressure of the AC system fluctuates depending on several factors, such as the ambient temperature, age, and the amount of refrigerant in the system. This switch is designed to make sure that the pressure stays at a consistent level so that the AC can function correctly.
As this switch continuously cycles on and off, the AC system operates its electrical contacts which subjects the switch to a high amount of wear. Over time, the contacts wear out and the switch must be replaced for the AC to function. When the clutch switch has failed, it will usually produce a few simple symptoms to look out for.
1. Lack of cooling
If you begin to notice that the AC system is not blowing as cold as it used to, then that may be a sign that the switch has failed, or is beginning to fail. If the switch is not operating correctly, the AC system will not be pressurized correctly and will not work as efficiently in cooling the air. If you notice that the AC is no longer blowing the same cold air as it used to, you may want to consider looking at the switch.
2. No cooling at all
In more severe cases, where the switch has completely failed, your AC system will completely cease to blow cold air. Without the cycling switch to activate the compressor’s clutch, the AC system will not be pressurized correctly, and the system will be unable to produce any cold air as a result.
If you begin to notice that the AC system is no longer functioning as it used to, and you suspect that the clutch cycling switch may have a problem, consider having the switch tested and replaced if necessary. It is also important to be aware that when replacing the clutch cycling switch, the AC system will need to be refilled with the proper amount of oil and refrigerant for the AC system. However, this is something that any professional technician, such as one from YourMechanic, should be able to take care of for you both quickly and precisely.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing AC Clutch Cycling Switch and was authored by Eduardo Ruelas.