What is the AC Clutch Cycling Switch all about?

You may think that the compressor or the compressor clutch are the most likely components to fail on a car’s air conditioning system, and they are high-wear items. However, 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 replaced.

Keep in mind:

• The AC clutch cycling switch is one of the most wear-prone components on your air conditioner.
• The switch is not inspected during regular maintenance and will only be checked if there’s a problem with the system.

How it's done:

• The AC clutch cycling switch is verified to see if it needs to be replaced
• The defective AC clutch cycling switch is removed
• The new AC clutch cycling switch is installed
• The AC clutch cycling switch is tested for operation
• The AC is tested to ensure proper operation of the AC clutch cycling switch

Our recommendation:

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 prevent 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 our expert mechanics diagnose your system.

What common symptoms indicate you may need to replace 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)

How important is 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 replacing a failed cycling switch.