What is the AC Clutch Cycling Switch?
You may think that the compressor or the compressor clutch is the most likely components to fail on a car’s air conditioning system, and they are high-wear items. But, the AC clutch cycling switch is actually the most common part to fail on many vehicles. The switch has a simple job, but it must engage and disengage every time the compressor cycles. This creates significant wear and tear, and leads to eventual failure.
Really, the name says it all when it comes to what this switch does. The AC cycling switch opens when the low side AC system pressure drops too low to allow pressure from the high side to equalize the system and keep refrigerant flowing through the entire air conditioner. The most common problem with the switch is with the contacts – wear and burning render them inoperable. If this happens, the entire switch must be changed.
Bear in mind:
The AC clutch cycling switch is one of the most wear-prone components on your air conditioner.
The switch is not examined during regular upkeep and will only be checked if there’s a problem with the system.
How to Fix:
The AC clutch cycling switch is confirmed to see if it needs to be changed
The faulty AC clutch cycling switch is removed
The new AC clutch cycling switch is fixed
The AC clutch cycling switch is tested for operation
The AC is tested to ensure proper operation of the AC clutch cycling switch
If the AC clutch cycling switch is not operational, then the system will not be able to equalize pressure and keep refrigerant flowing. This may activate the safety switch (generally, the low pressure switch), and the system will shut down in order to try to stop damage. However, if the system doesn’t shut down, compressor clutch damage is very likely. Don’t run the AC if you suspect there’s a problem, and have one of your expert mechanics diagnose your system.
Common signs indicating you may need to change the AC Clutch Cycling Switch:
AC system not cooling as normal
AC system not cooling at all
Clutch will not engage (a sign of systemic damage, possibly caused initially by a failing clutch cycling switch)
Importance of this service:
It is vital that your car’s air conditioner have an operational AC clutch cycling switch. If the switch begins to fail, the voltage sent to the clutch drops, which reduces the clutch’s holding power. Over time, this will cause the clutch to fail. Many cars today require the replacement of the entire clutch/compressor assembly, which is much more expensive than just changing a failed cycling switch.