There is a flat plate on the front of the compressor. Like the previous missive said, it's just under the alternator. When the clutch engages, the a/c is running. That flat plate is the clutch. It's what turns the compressor on and off. When it's working, a magnetic clutch pulls it in and it locks the belt to turn the compressor. When you turn the system off, or the safety switch shuts it off, the plate pops out and releases the belt. This lets the belt keep moving and the compressor doesn't turn, just the pulley on the front of it.

I have a 2013 cx-5, a/c was barely working, but guage on recharge kit showed good. I took the blower fan apart, thinking it was clogged, and found the cheap little filter they install behind the glove box to protect the blower. completely clogged up, no air flow at all. replaced it, and all working great now

The cabin air filter should be changed at least yearly.
Improves air flow for AC & heat and the smell of whatever is caught in it, yeah even dead rodents.
Unfortunately, most people don't even know they exist.
.

The smells really not caught in most of the cabin filters on the market. Beware of some claiming to as they only mask issues with scents. The only way to rid the smells from using the AC is by cleaning the AC system from the cabin filter into the HVAC system.
Very easy for even DIY and takes about an hour.

Apparently, I wasn't so good with the wording in my comment
What I meant by "smell caught" was the smells of whatever had been accumulating in the filter since the last change.

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